Features * High Performance, Low Power AVR(R) 8-Bit Microcontroller * Advanced RISC Architecture * * * * * * * * - 131 Powerful Instructions - Most Single Clock Cycle Execution - 32 x 8 General Purpose Working Registers - Fully Static Operation - Up to 20 MIPS Throughput at 20 MHz - On-chip 2-cycle Multiplier Non-volatile Program and Data Memories - 4/8/16K Bytes of In-System Self-Programmable Flash (ATmega48/88/168) Endurance: 10,000 Write/Erase Cycles - Optional Boot Code Section with Independent Lock Bits In-System Programming by On-chip Boot Program True Read-While-Write Operation - 256/512/512 Bytes EEPROM (ATmega48/88/168) Endurance: 100,000 Write/Erase Cycles - 512/1K/1K Byte Internal SRAM (ATmega48/88/168) - Programming Lock for Software Security Peripheral Features - Two 8-bit Timer/Counters with Separate Prescaler and Compare Mode - One 16-bit Timer/Counter with Separate Prescaler, Compare Mode, and Capture Mode - Real Time Counter with Separate Oscillator - Six PWM Channels - 8-channel 10-bit ADC in TQFP and MLF package - 6-channel 10-bit ADC in PDIP Package - Programmable Serial USART - Master/Slave SPI Serial Interface - Byte-oriented 2-wire Serial Interface - Programmable Watchdog Timer with Separate On-chip Oscillator - On-chip Analog Comparator - Interrupt and Wake-up on Pin Change Special Microcontroller Features - Power-on Reset and Programmable Brown-out Detection - Internal Calibrated Oscillator - External and Internal Interrupt Sources - Five Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, and Standby I/O and Packages - 23 Programmable I/O Lines - 28-pin PDIP, 32-lead TQFP and 32-pad MLF Operating Voltage: - 1.8 - 5.5V for ATmega48V/88V/168V - 2.7 - 5.5V for ATmega48/88/168 Temperature Range: - -40C to 85C Speed Grade: - ATmega48V/88V/168V: 0 - 4 MHz @ 1.8 - 5.5V, 0 - 10 MHz @ 2.7 - 5.5V - ATmega48/88/168: 0 - 10 MHz @ 2.7 - 5.5V, 0 - 20 MHz @ 4.5 - 5.5V Low Power Consumption - Active Mode: 1 MHz, 1.8V: 240A 32 kHz, 1.8V: 15A (including Oscillator) - Power-down Mode: 0.1A at 1.8V 8-bit Microcontroller with 8K Bytes In-System Programmable Flash ATmega48/V ATmega88/V ATmega168/V Preliminary Summary 2545DS-AVR-07/04 Note: This is a summary document. A complete document is available on our Web site at www.atmel.com. Pin Configurations Figure 1. Pinout ATmega48/88/168 PDIP (PCINT14/RESET) PC6 (PCINT16/RXD) PD0 (PCINT17/TXD) PD1 (PCINT18/INT0) PD2 (PCINT19/OC2B/INT1) PD3 (PCINT20/XCK/T0) PD4 VCC GND (PCINT6/XTAL1/TOSC1) PB6 (PCINT7/XTAL2/TOSC2) PB7 (PCINT21/OC0B/T1) PD5 (PCINT22/OC0A/AIN0) PD6 (PCINT23/AIN1) PD7 (PCINT0/CLKO/ICP1) PB0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 PC5 (ADC5/SCL/PCINT13) PC4 (ADC4/SDA/PCINT12) PC3 (ADC3/PCINT11) PC2 (ADC2/PCINT10) PC1 (ADC1/PCINT9) PC0 (ADC0/PCINT8) GND AREF AVCC PB5 (SCK/PCINT5) PB4 (MISO/PCINT4) PB3 (MOSI/OC2A/PCINT3) PB2 (SS/OC1B/PCINT2) PB1 (OC1A/PCINT1) MLF Top View 32 31 30 29 28 27 26 25 32 31 30 29 28 27 26 25 PD2 (INT0/PCINT18) PD1 (TXD/PCINT17) PD0 (RXD/PCINT16) PC6 (RESET/PCINT14) PC5 (ADC5/SCL/PCINT13) PC4 (ADC4/SDA/PCINT12) PC3 (ADC3/PCINT11) PC2 (ADC2/PCINT10) PD2 (INT0/PCINT18) PD1 (TXD/PCINT17) PD0 (RXD/PCINT16) PC6 (RESET/PCINT14) PC5 (ADC5/SCL/PCINT13) PC4 (ADC4/SDA/PCINT12) PC3 (ADC3/PCINT11) PC2 (ADC2/PCINT10) TQFP Top View (PCINT19/OC2B/INT1) PD3 (PCINT20/XCK/T0) PD4 GND VCC GND VCC (PCINT6/XTAL1/TOSC1) PB6 (PCINT7/XTAL2/TOSC2) PB7 (PCINT21/OC0B/T1) PD5 (PCINT22/OC0A/AIN0) PD6 (PCINT23/AIN1) PD7 (PCINT0/CLKO/ICP1) PB0 (PCINT1/OC1A) PB1 (PCINT2/SS/OC1B) PB2 (PCINT3/OC2A/MOSI) PB3 (PCINT4/MISO) PB4 Disclaimer 2 24 23 22 21 20 19 18 17 1 2 3 4 5 6 7 8 PC1 (ADC1/PCINT9) PC0 (ADC0/PCINT8) ADC7 GND AREF ADC6 AVCC PB5 (SCK/PCINT5) 9 10 11 12 13 14 15 16 PC1 (ADC1/PCINT9) PC0 (ADC0/PCINT8) ADC7 GND AREF ADC6 AVCC PB5 (SCK/PCINT5) NOTE: Bottom pad should be soldered to ground. (PCINT21/OC0B/T1) PD5 (PCINT22/OC0A/AIN0) PD6 (PCINT23/AIN1) PD7 (PCINT0/CLKO/ICP1) PB0 (PCINT1/OC1A) PB1 (PCINT2/SS/OC1B) PB2 (PCINT3/OC2A/MOSI) PB3 (PCINT4/MISO) PB4 24 23 22 21 20 19 18 17 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 (PCINT19/OC2B/INT1) PD3 (PCINT20/XCK/T0) PD4 GND VCC GND VCC (PCINT6/XTAL1/TOSC1) PB6 (PCINT7/XTAL2/TOSC2) PB7 Typical values contained in this datasheet are based on simulations and characterization of other AVR microcontrollers manufactured on the same process technology. Min and Max values will be available after the device is characterized. ATmega48/88/168 2545DS-AVR-07/04 ATmega48/88/168 The ATmega48/88/168 is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the ATmega48/88/168 achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed. Block Diagram Figure 2. Block Diagram GND VCC Overview Watchdog Timer Watchdog Oscillator Oscillator Circuits / Clock Generation Power Supervision POR / BOD & RESET debugWIRE Flash SRAM PROGRAM LOGIC CPU EEPROM AVCC AREF DATABUS GND 8bit T/C 0 16bit T/C 1 A/D Conv. 8bit T/C 2 Analog Comp. Internal Bandgap USART 0 SPI TWI PORT D (8) PORT B (8) PORT C (7) 2 6 RESET XTAL[1..2] PD[0..7] PB[0..7] PC[0..6] ADC[6..7] 3 2545DS-AVR-07/04 The AVR core combines a rich instruction set with 32 general purpose working registers. All the 32 registers are directly connected to the Arithmetic Logic Unit (ALU), allowing two independent registers to be accessed in one single instruction executed in one clock cycle. The resulting architecture is more code efficient while achieving throughputs up to ten times faster than conventional CISC microcontrollers. The ATmega48/88/168 provides the following features: 4K/8K/16K bytes of In-System Programmable Flash with Read-While-Write capabilities, 256/512/512 bytes EEPROM, 512/1K/1K bytes SRAM, 23 general purpose I/O lines, 32 general purpose working registers, three flexible Timer/Counters with compare modes, internal and external interrupts, a serial programmable USART, a byte-oriented 2-wire Serial Interface, an SPI serial port, a 6-channel 10-bit ADC (8 channels in TQFP and MLF packages), a programmable Watchdog Timer with internal Oscillator, and five software selectable power saving modes. The Idle mode stops the CPU while allowing the SRAM, Timer/Counters, USART, 2-wire Serial Interface, SPI port, and interrupt system to continue functioning. The Power-down mode saves the register contents but freezes the Oscillator, disabling all other chip functions until the next interrupt or hardware reset. In Power-save mode, the asynchronous timer continues to run, allowing the user to maintain a timer base while the rest of the device is sleeping. The ADC Noise Reduction mode stops the CPU and all I/O modules except asynchronous timer and ADC, to minimize switching noise during ADC conversions. In Standby mode, the crystal/resonator Oscillator is running while the rest of the device is sleeping. This allows very fast start-up combined with low power consumption. The device is manufactured using Atmel's high density non-volatile memory technology. The On-chip ISP Flash allows the program memory to be reprogrammed In-System through an SPI serial interface, by a conventional non-volatile memory programmer, or by an On-chip Boot program running on the AVR core. The Boot program can use any interface to download the application program in the Application Flash memory. Software in the Boot Flash section will continue to run while the Application Flash section is updated, providing true Read-While-Write operation. By combining an 8-bit RISC CPU with In-System Self-Program mable Flash on a monolithic ch ip, the Atmel ATmega48/88/168 is a powerful microcontroller that provides a highly flexible and cost effective solution to many embedded control applications. The ATmega48/88/168 AVR is supported with a full suite of program and system development tools including: C Compilers, Macro Assemblers, Program Debugger/Simulators, In-Circuit Emulators, and Evaluation kits. Comparison Between ATmega48, ATmega88, and ATmega168 The ATmega48, ATmega88 and ATmega168 differ only in memory sizes, boot loader support, and interrupt vector sizes. Table 1 summarizes the different memory and interrupt vector sizes for the three devices. Table 1. Memory Size Summary Device Flash EEPROM RAM Interrupt Vector Size ATmega48 4K Bytes 256 Bytes 512 Bytes 1 instruction word/vector ATmega88 8K Bytes 512 Bytes 1K Bytes 1 instruction word/vector ATmega168 16K Bytes 512 Bytes 1K Bytes 2 instruction words/vector ATmega88 and ATmega168 support a real Read-While-Write Self-Programming mechanism. There is a separate Boot Loader Section, and the SPM instruction can only execute from there. In ATmega48, there is no Read-While-Write support and no separate Boot Loader Section. The SPM instruction can execute from the entire Flash. 4 ATmega48/88/168 2545DS-AVR-07/04 ATmega48/88/168 Pin Descriptions VCC Digital supply voltage. GND Ground. Port B (PB7..0) XTAL1/ XTAL2/TOSC1/TOSC2 Port B is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The Port B output buffers have symmetrical drive characteristics with both high sink and source capability. As inputs, Port B pins that are externally pulled low will source current if the pull-up resistors are activated. The Port B pins are tri-stated when a reset condition becomes active, even if the clock is not running. Depending on the clock selection fuse settings, PB6 can be used as input to the inverting Oscillator amplifier and input to the internal clock operating circuit. Depending on the clock selection fuse settings, PB7 can be used as output from the inverting Oscillator amplifier. If the Internal Calibrated RC Oscillator is used as chip clock source, PB7..6 is used as TOSC2..1 input for the Asynchronous Timer/Counter2 if the AS2 bit in ASSR is set. The various special features of Port B are elaborated in "Alternate Functions of Port B" on page 69 and "System Clock and Clock Options" on page 24. Port C (PC5..0) Port C is a 7-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The PC5..0 output buffers have symmetrical drive characteristics with both high sink and source capability. As inputs, Port C pins that are externally pulled low will source current if the pull-up resistors are activated. The Port C pins are tri-stated when a reset condition becomes active, even if the clock is not running. PC6/RESET If the RSTDISBL Fuse is programmed, PC6 is used as an I/O pin. Note that the electrical characteristics of PC6 differ from those of the other pins of Port C. If the RSTDISBL Fuse is unprogrammed, PC6 is used as a Reset input. A low level on this pin for longer than the minimum pulse length will generate a Reset, even if the clock is not running. The minimum pulse length is given in Table 20 on page 41. Shorter pulses are not guaranteed to generate a Reset. The various special features of Port C are elaborated in "Alternate Functions of Port C" on page 73. Port D (PD7..0) Port D is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for each bit). The Port D output buffers have symmetrical drive characteristics with both high sink and source capability. As inputs, Port D pins that are externally pulled low will source current if the pull-up resistors are activated. The Port D pins are tri-stated when a reset condition becomes active, even if the clock is not running. The various special features of Port D are elaborated in "Alternate Functions of Port D" on page 75. AVCC AVCC is the supply voltage pin for the A/D Converter, PC3..0, and ADC7..6. It should be externally connected to VCC, even if the ADC is not used. If the ADC is used, it should be connected to VCC through a low-pass filter. Note that PC6..4 use digital supply voltage, VCC. AREF AREF is the analog reference pin for the A/D Converter. 5 2545DS-AVR-07/04 ADC7..6 In the TQFP and MLF package, ADC7..6 serve as analog inputs to the A/D converter. (TQFP and MLF Package Only) These pins are powered from the analog supply and serve as 10-bit ADC channels. 6 ATmega48/88/168 2545DS-AVR-07/04 ATmega48/88/168 Register Summary Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 (0xFF) Reserved - - - - - - - - (0xFE) Reserved - - - - - - - - (0xFD) Reserved - - - - - - - - (0xFC) Reserved - - - - - - - - (0xFB) Reserved - - - - - - - - (0xFA) Reserved - - - - - - - - (0xF9) Reserved - - - - - - - - (0xF8) Reserved - - - - - - - - (0xF7) Reserved - - - - - - - - (0xF6) Reserved - - - - - - - - (0xF5) Reserved - - - - - - - - (0xF4) Reserved - - - - - - - - (0xF3) Reserved - - - - - - - - (0xF2) Reserved - - - - - - - - (0xF1) Reserved - - - - - - - - (0xF0) Reserved - - - - - - - - (0xEF) Reserved - - - - - - - - (0xEE) Reserved - - - - - - - - (0xED) Reserved - - - - - - - - (0xEC) Reserved - - - - - - - - (0xEB) Reserved - - - - - - - - (0xEA) Reserved - - - - - - - - (0xE9) Reserved - - - - - - - - (0xE8) Reserved - - - - - - - - (0xE7) Reserved - - - - - - - - (0xE6) Reserved - - - - - - - - (0xE5) Reserved - - - - - - - - (0xE4) Reserved - - - - - - - - (0xE3) Reserved - - - - - - - - (0xE2) Reserved - - - - - - - - (0xE1) Reserved - - - - - - - - (0xE0) Reserved - - - - - - - - (0xDF) Reserved - - - - - - - - (0xDE) Reserved - - - - - - - - (0xDD) Reserved - - - - - - - - (0xDC) Reserved - - - - - - - - (0xDB) Reserved - - - - - - - - (0xDA) Reserved - - - - - - - - (0xD9) Reserved - - - - - - - - (0xD8) Reserved - - - - - - - - (0xD7) Reserved - - - - - - - - (0xD6) Reserved - - - - - - - - (0xD5) Reserved - - - - - - - - (0xD4) Reserved - - - - - - - - (0xD3) Reserved - - - - - - - - (0xD2) Reserved - - - - - - - - (0xD1) Reserved - - - - - - - - (0xD0) Reserved - - - - - - - - (0xCF) Reserved - - - - - - - - (0xCE) Reserved - - - - - - - - (0xCD) Reserved - - - - - - - - (0xCC) Reserved - - - - - - - - (0xCB) Reserved - - - - - - - - (0xCA) Reserved - - - - - - - - (0xC9) Reserved - - - - - - - - (0xC8) Reserved - - - - - - - - (0xC7) Reserved - - - - - - - - (0xC6) UDR0 (0xC5) UBRR0H USART I/O Data Register 180 USART Baud Rate Register High (0xC4) UBRR0L (0xC3) Reserved - - 184 USART Baud Rate Register Low - Page 184 - - - - - (0xC2) UCSR0C UMSEL01 UMSEL00 UPM01 UPM00 USBS0 UCSZ01 /UDORD0 UCSZ00 / UCPHA0 UCPOL0 (0xC1) UCSR0B RXCIE0 TXCIE0 UDRIE0 RXEN0 TXEN0 UCSZ02 RXB80 TXB80 182 (0xC0) UCSR0A RXC0 TXC0 UDRE0 FE0 DOR0 UPE0 U2X0 MPCM0 180 183/196 7 2545DS-AVR-07/04 8 Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 (0xBF) Reserved - - - - - - - - - Page (0xBE) Reserved - - - - - - - (0xBD) TWAMR TWAM6 TWAM5 TWAM4 TWAM3 TWAM2 TWAM1 TWAM0 - 209 (0xBC) TWCR TWINT TWEA TWSTA TWSTO TWWC TWEN - TWIE 206 (0xBB) TWDR (0xBA) TWAR TWA6 TWA5 TWA4 TWS7 TWS6 TWS5 2-wire Serial Interface Data Register (0xB9) TWSR (0xB8) TWBR (0xB7) Reserved - (0xB6) ASSR - (0xB5) Reserved - 208 TWA3 TWA2 TWA1 TWA0 TWGCE 208 TWS4 TWS3 - TWPS1 TWPS0 207 2-wire Serial Interface Bit Rate Register 206 - - - - - - EXCLK AS2 TCN2UB OCR2AUB OCR2BUB TCR2AUB TCR2BUB - - - - - - - 150 (0xB4) OCR2B Timer/Counter2 Output Compare Register B 147 (0xB3) OCR2A Timer/Counter2 Output Compare Register A 147 (0xB2) TCNT2 (0xB1) TCCR2B FOC2A FOC2B - Timer/Counter2 (8-bit) - WGM22 CS22 CS21 CS20 147 146 (0xB0) TCCR2A COM2A1 COM2A0 COM2B1 COM2B0 - - WGM21 WGM20 143 (0xAF) Reserved - - - - - - - - (0xAE) Reserved - - - - - - - - (0xAD) Reserved - - - - - - - - (0xAC) Reserved - - - - - - - - (0xAB) Reserved - - - - - - - - (0xAA) Reserved - - - - - - - - (0xA9) Reserved - - - - - - - - (0xA8) Reserved - - - - - - - - (0xA7) Reserved - - - - - - - - (0xA6) Reserved - - - - - - - - (0xA5) Reserved - - - - - - - - (0xA4) Reserved - - - - - - - - (0xA3) Reserved - - - - - - - - (0xA2) Reserved - - - - - - - - (0xA1) Reserved - - - - - - - - (0xA0) Reserved - - - - - - - - (0x9F) Reserved - - - - - - - - (0x9E) Reserved - - - - - - - - (0x9D) Reserved - - - - - - - - (0x9C) Reserved - - - - - - - - (0x9B) Reserved - - - - - - - - (0x9A) Reserved - - - - - - - - (0x99) Reserved - - - - - - - - (0x98) Reserved - - - - - - - - (0x97) Reserved - - - - - - - - (0x96) Reserved - - - - - - - - (0x95) Reserved - - - - - - - - (0x94) Reserved - - - - - - - - (0x93) Reserved - - - - - - - - (0x92) Reserved - - - - - - - - (0x91) Reserved - - - - - - - - (0x90) Reserved - - - - - - - - (0x8F) Reserved - - - - - - - - (0x8E) Reserved - - - - - - - - (0x8D) Reserved - - - - - - - - (0x8C) Reserved - - - - - - - - (0x8B) OCR1BH Timer/Counter1 - Output Compare Register B High Byte 129 (0x8A) OCR1BL Timer/Counter1 - Output Compare Register B Low Byte 129 (0x89) OCR1AH Timer/Counter1 - Output Compare Register A High Byte 129 (0x88) OCR1AL Timer/Counter1 - Output Compare Register A Low Byte 129 (0x87) ICR1H Timer/Counter1 - Input Capture Register High Byte 129 (0x86) ICR1L Timer/Counter1 - Input Capture Register Low Byte 129 (0x85) TCNT1H Timer/Counter1 - Counter Register High Byte 129 (0x84) TCNT1L Timer/Counter1 - Counter Register Low Byte 129 (0x83) Reserved - - - - - - - (0x82) TCCR1C FOC1A FOC1B - - - - - - (0x81) TCCR1B ICNC1 ICES1 - WGM13 WGM12 CS12 CS11 CS10 127 (0x80) TCCR1A COM1A1 COM1A0 COM1B1 COM1B0 - - WGM11 WGM10 125 (0x7F) DIDR1 - - - - - - AIN1D AIN0D 230 (0x7E) DIDR0 - - ADC5D ADC4D ADC3D ADC2D ADC1D ADC0D 245 - 128 ATmega48/88/168 2545DS-AVR-07/04 ATmega48/88/168 Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 (0x7D) Reserved - - - - - - - - (0x7C) ADMUX REFS1 REFS0 ADLAR - MUX3 MUX2 MUX1 MUX0 241 (0x7B) ADCSRB - ACME - - - ADTS2 ADTS1 ADTS0 244 (0x7A) ADCSRA ADEN ADSC ADATE ADIF ADIE ADPS2 ADPS1 ADPS0 (0x79) ADCH ADC Data Register High byte Page 242 244 (0x78) ADCL (0x77) Reserved - - - ADC Data Register Low byte - - - - - 244 (0x76) Reserved - - - - - - - - (0x75) Reserved - - - - - - - - (0x74) Reserved - - - - - - - - (0x73) Reserved - - - - - - - - (0x72) Reserved - - - - - - - - (0x71) Reserved - - - - - - - - (0x70) TIMSK2 - - - - - OCIE2B OCIE2A TOIE2 148 (0x6F) TIMSK1 - - ICIE1 - - OCIE1B OCIE1A TOIE1 130 (0x6E) TIMSK0 - - - - - OCIE0B OCIE0A TOIE0 100 (0x6D) PCMSK2 PCINT23 PCINT22 PCINT21 PCINT20 PCINT19 PCINT18 PCINT17 PCINT16 83 (0x6C) PCMSK1 - PCINT14 PCINT13 PCINT12 PCINT11 PCINT10 PCINT9 PCINT8 83 (0x6B) PCMSK0 PCINT7 PCINT6 PCINT5 PCINT4 PCINT3 PCINT2 PCINT1 PCINT0 84 (0x6A) Reserved - - - - - - - - (0x69) EICRA - - - - ISC11 ISC10 ISC01 ISC00 (0x68) PCICR - - - - - PCIE2 PCIE1 PCIE0 (0x67) Reserved - - - - - - - - (0x66) OSCCAL (0x65) Reserved - - - - - - - - (0x64) PRR PRTWI PRTIM2 PRTIM0 - PRTIM1 PRSPI PRUSART0 PRADC (0x63) Reserved - - - - - - - - (0x62) Reserved - - - - - - - - (0x61) CLKPR CLKPCE - - - CLKPS3 CLKPS2 CLKPS1 CLKPS0 33 (0x60) WDTCSR WDIF WDIE WDP3 WDCE WDE WDP2 WDP1 WDP0 49 0x3F (0x5F) SREG I T H S V N Z C 9 0x3E (0x5E) SPH - - - - - (SP10) 5. SP9 SP8 11 0x3D (0x5D) SPL SP7 SP6 SP5 SP4 SP3 SP2 SP1 SP0 11 0x3C (0x5C) Reserved - - - - - - - - 0x3B (0x5B) Reserved - - - - - - - - 0x3A (0x5A) Reserved - - - - - - - - 0x39 (0x59) Reserved - - - - - - - - 0x38 (0x58) Reserved - - - - - - - - 0x37 (0x57) SPMCSR SPMIE (RWWSB)5. - (RWWSRE)5. BLBSET PGWRT PGERS SELFPRGEN 0x36 (0x56) Reserved - - - - - - - - 0x35 (0x55) MCUCR - - - PUD - - IVSEL IVCE 0x34 (0x54) MCUSR - - - - WDRF BORF EXTRF PORF 0x33 (0x53) SMCR - - - - SM2 SM1 SM0 SE 0x32 (0x52) Reserved - - - - - - - - 0x31 (0x51) Reserved - - - - - - - - 0x30 (0x50) ACSR ACD ACBG ACO ACI ACIE ACIC ACIS1 ACIS0 0x2F (0x4F) Reserved - - - - - - - - 0x2E (0x4E) SPDR 0x2D (0x4D) SPSR SPIF WCOL - - - - - SPI2X 160 0x2C (0x4C) SPCR SPIE SPE DORD MSTR CPOL CPHA SPR1 SPR0 158 0x2B (0x4B) GPIOR2 General Purpose I/O Register 2 0x2A (0x4A) GPIOR1 General Purpose I/O Register 1 0x29 (0x49) Reserved 0x28 (0x48) OCR0B Timer/Counter0 Output Compare Register B 0x27 (0x47) OCR0A Timer/Counter0 Output Compare Register A 0x26 (0x46) TCNT0 0x25 (0x45) TCCR0B FOC0A FOC0B - - WGM02 CS02 CS01 CS00 0x24 (0x44) TCCR0A COM0A1 COM0A0 COM0B1 COM0B0 - - WGM01 WGM00 0x23 (0x43) GTCCR TSM - - - - - PSRASY PSRSYNC 0x22 (0x42) EEARH (EEPROM Address Register High Byte) 5. 0x21 (0x41) EEARL EEPROM Address Register Low Byte 18 0x20 (0x40) EEDR EEPROM Data Register 18 Oscillator Calibration Register 30 SPI Data Register - - - - 80 37 260 35 228 160 23 23 - - - - Timer/Counter0 (8-bit) 0x1F (0x3F) EECR 0x1E (0x3E) GPIOR0 - - EEPM1 EEPM0 0x1D (0x3D) EIMSK - - - - 0x1C (0x3C) EIFR - - - - EERIE 103/152 18 EEMPE EEPE EERE 18 - - INT1 INT0 81 - - INTF1 INTF0 82 General Purpose I/O Register 0 23 9 2545DS-AVR-07/04 Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 0x1B (0x3B) PCIFR - - - - - PCIF2 PCIF1 PCIF0 Page 0x1A (0x3A) Reserved - - - - - - - - 0x19 (0x39) Reserved - - - - - - - - 0x18 (0x38) Reserved - - - - - - - - 0x17 (0x37) TIFR2 - - - - - OCF2B OCF2A TOV2 148 0x16 (0x36) TIFR1 - - ICF1 - - OCF1B OCF1A TOV1 130 0x15 (0x35) TIFR0 - - - - - OCF0B OCF0A TOV0 0x14 (0x34) Reserved - - - - - - - - 0x13 (0x33) Reserved - - - - - - - - 0x12 (0x32) Reserved - - - - - - - - 0x11 (0x31) Reserved - - - - - - - - 0x10 (0x30) Reserved - - - - - - - - 0x0F (0x2F) Reserved - - - - - - - - 0x0E (0x2E) Reserved - - - - - - - - 0x0D (0x2D) Reserved - - - - - - - - 0x0C (0x2C) Reserved - - - - - - - - 0x0B (0x2B) PORTD PORTD7 PORTD6 PORTD5 PORTD4 PORTD3 PORTD2 PORTD1 PORTD0 79 0x0A (0x2A) DDRD DDD7 DDD6 DDD5 DDD4 DDD3 DDD2 DDD1 DDD0 79 0x09 (0x29) PIND PIND7 PIND6 PIND5 PIND4 PIND3 PIND2 PIND1 PIND0 79 0x08 (0x28) PORTC - PORTC6 PORTC5 PORTC4 PORTC3 PORTC2 PORTC1 PORTC0 79 0x07 (0x27) DDRC - DDC6 DDC5 DDC4 DDC3 DDC2 DDC1 DDC0 79 0x06 (0x26) PINC - PINC6 PINC5 PINC4 PINC3 PINC2 PINC1 PINC0 79 0x05 (0x25) PORTB PORTB7 PORTB6 PORTB5 PORTB4 PORTB3 PORTB2 PORTB1 PORTB0 79 0x04 (0x24) DDRB DDB7 DDB6 DDB5 DDB4 DDB3 DDB2 DDB1 DDB0 79 0x03 (0x23) PINB PINB7 PINB6 PINB5 PINB4 PINB3 PINB2 PINB1 PINB0 79 0x02 (0x22) Reserved - - - - - - - - 0x01 (0x21) Reserved - - - - - - - - 0x0 (0x20) Reserved - - - - - - - - Note: 1. For compatibility with future devices, reserved bits should be written to zero if accessed. Reserved I/O memory addresses should never be written. 2. I/O Registers within the address range 0x00 - 0x1F are directly bit-accessible using the SBI and CBI instructions. In these registers, the value of single bits can be checked by using the SBIS and SBIC instructions. 3. Some of the Status Flags are cleared by writing a logical one to them. Note that, unlike most other AVRs, the CBI and SBI instructions will only operate on the specified bit, and can therefore be used on registers containing such Status Flags. The CBI and SBI instructions work with registers 0x00 to 0x1F only. 4. When using the I/O specific commands IN and OUT, the I/O addresses 0x00 - 0x3F must be used. When addressing I/O Registers as data space using LD and ST instructions, 0x20 must be added to these addresses. The ATmega48/88/168 is a complex microcontroller with more peripheral units than can be supported within the 64 location reserved in Opcode for the IN and OUT instructions. For the Extended I/O space from 0x60 - 0xFF in SRAM, only the ST/STS/STD and LD/LDS/LDD instructions can be used. 5. Only valid for ATmega88/168. 10 ATmega48/88/168 2545DS-AVR-07/04 ATmega48/88/168 Instruction Set Summary Mnemonics Operands Description Operation Flags #Clocks ARITHMETIC AND LOGIC INSTRUCTIONS ADD Rd, Rr Add two Registers Rd Rd + Rr Z,C,N,V,H ADC Rd, Rr Add with Carry two Registers Rd Rd + Rr + C Z,C,N,V,H 1 ADIW Rdl,K Add Immediate to Word Rdh:Rdl Rdh:Rdl + K Z,C,N,V,S 2 SUB Rd, Rr Subtract two Registers Rd Rd - Rr Z,C,N,V,H 1 SUBI Rd, K Subtract Constant from Register Rd Rd - K Z,C,N,V,H 1 SBC Rd, Rr Subtract with Carry two Registers Rd Rd - Rr - C Z,C,N,V,H 1 SBCI Rd, K Subtract with Carry Constant from Reg. Rd Rd - K - C Z,C,N,V,H 1 SBIW Rdl,K Subtract Immediate from Word Rdh:Rdl Rdh:Rdl - K Z,C,N,V,S 2 AND Rd, Rr Logical AND Registers Rd Rd * Rr Z,N,V 1 ANDI Rd, K Logical AND Register and Constant Rd Rd * K Z,N,V 1 OR Rd, Rr Logical OR Registers Rd Rd v Rr Z,N,V 1 ORI Rd, K Logical OR Register and Constant Rd Rd v K Z,N,V 1 EOR Rd, Rr Exclusive OR Registers Rd Rd Rr Z,N,V 1 1 COM Rd One's Complement Rd 0xFF - Rd Z,C,N,V 1 NEG Rd Two's Complement Rd 0x00 - Rd Z,C,N,V,H 1 SBR Rd,K Set Bit(s) in Register Rd Rd v K Z,N,V 1 CBR Rd,K Clear Bit(s) in Register Rd Rd * (0xFF - K) Z,N,V 1 INC Rd Increment Rd Rd + 1 Z,N,V 1 DEC Rd Decrement Rd Rd - 1 Z,N,V 1 TST Rd Test for Zero or Minus Rd Rd * Rd Z,N,V 1 CLR Rd Clear Register Rd Rd Rd Z,N,V 1 SER Rd Set Register Rd 0xFF None 1 MUL Rd, Rr Multiply Unsigned R1:R0 Rd x Rr Z,C 2 MULS Rd, Rr Multiply Signed R1:R0 Rd x Rr Z,C 2 MULSU Rd, Rr Multiply Signed with Unsigned R1:R0 Rd x Rr Z,C 2 FMUL Rd, Rr Fractional Multiply Unsigned R1:R0 (Rd x Rr) << 1 R1:R0 (Rd x Rr) << 1 R1:R0 (Rd x Rr) << 1 Z,C 2 Z,C 2 Z,C 2 2 FMULS Rd, Rr Fractional Multiply Signed FMULSU Rd, Rr Fractional Multiply Signed with Unsigned BRANCH INSTRUCTIONS RJMP k IJMP Relative Jump PC PC + k + 1 None Indirect Jump to (Z) PC Z None 2 JMP(1) k Direct Jump PC k None 3 RCALL k Relative Subroutine Call PC PC + k + 1 None 3 Indirect Call to (Z) PC Z None 3 Direct Subroutine Call PC k None 4 RET Subroutine Return PC STACK None 4 RETI Interrupt Return PC STACK I 4 ICALL CALL(1) k CPSE Rd,Rr Compare, Skip if Equal if (Rd = Rr) PC PC + 2 or 3 None CP Rd,Rr Compare Rd - Rr Z, N,V,C,H 1 CPC Rd,Rr Compare with Carry Rd - Rr - C Z, N,V,C,H 1 CPI Rd,K Compare Register with Immediate Rd - K Z, N,V,C,H SBRC Rr, b Skip if Bit in Register Cleared if (Rr(b)=0) PC PC + 2 or 3 None 1/2/3 1/2/3 1 SBRS Rr, b Skip if Bit in Register is Set if (Rr(b)=1) PC PC + 2 or 3 None 1/2/3 SBIC P, b Skip if Bit in I/O Register Cleared if (P(b)=0) PC PC + 2 or 3 None 1/2/3 SBIS P, b Skip if Bit in I/O Register is Set if (P(b)=1) PC PC + 2 or 3 None 1/2/3 BRBS s, k Branch if Status Flag Set if (SREG(s) = 1) then PCPC+k + 1 None 1/2 BRBC s, k Branch if Status Flag Cleared if (SREG(s) = 0) then PCPC+k + 1 None 1/2 BREQ k Branch if Equal if (Z = 1) then PC PC + k + 1 None 1/2 BRNE k Branch if Not Equal if (Z = 0) then PC PC + k + 1 None 1/2 BRCS k Branch if Carry Set if (C = 1) then PC PC + k + 1 None 1/2 BRCC k Branch if Carry Cleared if (C = 0) then PC PC + k + 1 None 1/2 BRSH k Branch if Same or Higher if (C = 0) then PC PC + k + 1 None 1/2 BRLO k Branch if Lower if (C = 1) then PC PC + k + 1 None 1/2 BRMI k Branch if Minus if (N = 1) then PC PC + k + 1 None 1/2 BRPL k Branch if Plus if (N = 0) then PC PC + k + 1 None 1/2 BRGE k Branch if Greater or Equal, Signed if (N V= 0) then PC PC + k + 1 None 1/2 BRLT k Branch if Less Than Zero, Signed if (N V= 1) then PC PC + k + 1 None 1/2 BRHS k Branch if Half Carry Flag Set if (H = 1) then PC PC + k + 1 None 1/2 BRHC k Branch if Half Carry Flag Cleared if (H = 0) then PC PC + k + 1 None 1/2 BRTS k Branch if T Flag Set if (T = 1) then PC PC + k + 1 None 1/2 BRTC k Branch if T Flag Cleared if (T = 0) then PC PC + k + 1 None 1/2 BRVS k Branch if Overflow Flag is Set if (V = 1) then PC PC + k + 1 None 1/2 BRVC k Branch if Overflow Flag is Cleared if (V = 0) then PC PC + k + 1 None 1/2 11 2545DS-AVR-07/04 Mnemonics Operands Description Operation Flags #Clocks BRIE k Branch if Interrupt Enabled if ( I = 1) then PC PC + k + 1 None 1/2 BRID k Branch if Interrupt Disabled if ( I = 0) then PC PC + k + 1 None 1/2 BIT AND BIT-TEST INSTRUCTIONS SBI P,b Set Bit in I/O Register I/O(P,b) 1 None 2 CBI P,b Clear Bit in I/O Register I/O(P,b) 0 None 2 LSL Rd Logical Shift Left Rd(n+1) Rd(n), Rd(0) 0 Z,C,N,V 1 LSR Rd Logical Shift Right Rd(n) Rd(n+1), Rd(7) 0 Z,C,N,V 1 ROL Rd Rotate Left Through Carry Rd(0)C,Rd(n+1) Rd(n),CRd(7) Z,C,N,V 1 ROR Rd Rotate Right Through Carry Rd(7)C,Rd(n) Rd(n+1),CRd(0) Z,C,N,V 1 ASR Rd Arithmetic Shift Right Rd(n) Rd(n+1), n=0..6 Z,C,N,V 1 SWAP Rd Swap Nibbles Rd(3..0)Rd(7..4),Rd(7..4)Rd(3..0) None 1 BSET s Flag Set SREG(s) 1 SREG(s) 1 BCLR s Flag Clear SREG(s) 0 SREG(s) 1 BST Rr, b Bit Store from Register to T T Rr(b) T 1 BLD Rd, b Bit load from T to Register Rd(b) T None 1 SEC Set Carry C1 C 1 CLC Clear Carry C0 C 1 SEN Set Negative Flag N1 N 1 CLN Clear Negative Flag N0 N 1 SEZ Set Zero Flag Z1 Z 1 CLZ Clear Zero Flag Z0 Z 1 SEI Global Interrupt Enable I1 I 1 CLI Global Interrupt Disable I0 I 1 SES Set Signed Test Flag S1 S 1 CLS Clear Signed Test Flag S0 S 1 SEV Set Twos Complement Overflow. V1 V 1 CLV Clear Twos Complement Overflow V0 V 1 SET Set T in SREG T1 T 1 CLT Clear T in SREG T0 T 1 SEH CLH Set Half Carry Flag in SREG Clear Half Carry Flag in SREG H1 H0 H H 1 1 Rd Rr Rd+1:Rd Rr+1:Rr None 1 None 1 1 DATA TRANSFER INSTRUCTIONS MOV Rd, Rr Move Between Registers MOVW Rd, Rr Copy Register Word LDI Rd, K Load Immediate Rd K None LD Rd, X Load Indirect Rd (X) None 2 LD Rd, X+ Load Indirect and Post-Inc. Rd (X), X X + 1 None 2 2 LD Rd, - X Load Indirect and Pre-Dec. X X - 1, Rd (X) None LD Rd, Y Load Indirect Rd (Y) None 2 LD Rd, Y+ Load Indirect and Post-Inc. Rd (Y), Y Y + 1 None 2 LD Rd, - Y Load Indirect and Pre-Dec. Y Y - 1, Rd (Y) None 2 LDD Rd,Y+q Load Indirect with Displacement Rd (Y + q) None 2 LD Rd, Z Load Indirect Rd (Z) None 2 LD Rd, Z+ Load Indirect and Post-Inc. Rd (Z), Z Z+1 None 2 LD Rd, -Z Load Indirect and Pre-Dec. Z Z - 1, Rd (Z) None 2 LDD Rd, Z+q Load Indirect with Displacement Rd (Z + q) None 2 LDS Rd, k Load Direct from SRAM Rd (k) None 2 ST X, Rr Store Indirect (X) Rr None 2 ST X+, Rr Store Indirect and Post-Inc. (X) Rr, X X + 1 None 2 ST - X, Rr Store Indirect and Pre-Dec. X X - 1, (X) Rr None 2 ST Y, Rr Store Indirect (Y) Rr None 2 ST Y+, Rr Store Indirect and Post-Inc. (Y) Rr, Y Y + 1 None 2 ST - Y, Rr Store Indirect and Pre-Dec. Y Y - 1, (Y) Rr None 2 STD Y+q,Rr Store Indirect with Displacement (Y + q) Rr None 2 ST Z, Rr Store Indirect (Z) Rr None 2 ST Z+, Rr Store Indirect and Post-Inc. (Z) Rr, Z Z + 1 None 2 ST -Z, Rr Store Indirect and Pre-Dec. Z Z - 1, (Z) Rr None 2 STD Z+q,Rr Store Indirect with Displacement (Z + q) Rr None 2 STS k, Rr Store Direct to SRAM (k) Rr None 2 Load Program Memory R0 (Z) None 3 LPM LPM Rd, Z Load Program Memory Rd (Z) None 3 LPM Rd, Z+ Load Program Memory and Post-Inc Rd (Z), Z Z+1 None 3 Store Program Memory (Z) R1:R0 None - IN Rd, P In Port Rd P None 1 OUT P, Rr Out Port P Rr None 1 PUSH Rr Push Register on Stack STACK Rr None 2 SPM 12 ATmega48/88/168 2545DS-AVR-07/04 ATmega48/88/168 Mnemonics POP Operands Rd Description Pop Register from Stack Operation Rd STACK Flags #Clocks None 2 MCU CONTROL INSTRUCTIONS NOP No Operation None 1 SLEEP Sleep (see specific descr. for Sleep function) None 1 WDR BREAK Watchdog Reset Break (see specific descr. for WDR/timer) For On-chip Debug Only None None 1 N/A Note: 1. These instructions are only available in ATmega168. 13 2545DS-AVR-07/04 Ordering Information ATmega48 Speed (MHz) 10(3) 20(3) Note: Power Supply Ordering Code Package Operation Range 1.8 - 5.5 ATmega48V-10AI ATmega48V-10PI ATmega48V-10MI ATmega48V-10AJ(2) ATmega48V-10PJ(2) ATmega48V-10MJ(2) 32A 28P3 32M1-A 32A 28P3 32M1-A Industrial (-40C to 85C) 2.7 - 5.5 ATmega48-20AI ATmega48-20PI ATmega48-20MI ATmega48-20AJ(2) ATmega48-20PJ(2) ATmega48-20MJ(2) 32A 28P3 32M1-A 32A 28P3 32M1-A Industrial (-40C to 85C) 1. This device can also be supplied in wafer form. Please contact your local Atmel sales office for detailed ordering information and minimum quantities. 2. Pb-free packaging alternative 3. See Figure 131 on page 293 and Figure 132 on page 293. Package Type 32A 32-lead, Thin (1.0 mm) Plastic Quad Flat Package (TQFP) 28P3 28-lead, 0.300" Wide, Plastic Dual Inline Package (PDIP) 32M1-A 32-pad, 5 x 5 x 1.0 body, Lead Pitch 0.50 mm Micro Lead Frame Package (MLF) 14 ATmega48/88/168 2545DS-AVR-07/04 ATmega48/88/168 ATmega88 Speed (MHz) 10(3) 20(3) Note: Power Supply Ordering Code Package Operation Range 1.8 - 5.5 ATmega88V-10AI ATmega88V-10PI ATmega88V-10MI ATmega88V-10AJ(2) ATmega88V-10PJ(2) ATmega88V-10MJ(2) 32A 28P3 32M1-A 32A 28P3 32M1-A Industrial (-40C to 85C) 2.7 - 5.5 ATmega88-20AI ATmega88-20PI ATmega88-20MI ATmega88-20AJ(2) ATmega88-20PJ(2) ATmega88-20MJ(2) 32A 28P3 32M1-A 32A 28P3 32M1-A Industrial (-40C to 85C) 1. This device can also be supplied in wafer form. Please contact your local Atmel sales office for detailed ordering information and minimum quantities. 2. Pb-free packaging alternative 3. See Figure 131 on page 293 and Figure 132 on page 293. Package Type 32A 32-lead, Thin (1.0 mm) Plastic Quad Flat Package (TQFP) 28P3 28-lead, 0.300" Wide, Plastic Dual Inline Package (PDIP) 32M1-A 32-pad, 5 x 5 x 1.0 body, Lead Pitch 0.50 mm Micro Lead Frame Package (MLF) 15 2545DS-AVR-07/04 ATmega168 Speed (MHz) 10(3) 20(3) Note: Power Supply Ordering Code Package Operation Range 1.8 - 5.5 ATmega168V-10AI ATmega168V-10PI ATmega168V-10MI ATmega168V-10AJ(2) ATmega168V-10PJ(2) ATmega168V-10MJ(2) 32A 28P3 32M1-A 32A 28P3 32M1-A Industrial (-40C to 85C) 2.7 - 5.5 ATmega168-20AI ATmega168-20PI ATmega168-20MI ATmega168-20AJ(2) ATmega168-20PJ(2) ATmega168-20MJ(2) 32A 28P3 32M1-A 32A 28P3 32M1-A Industrial (-40C to 85C) 1. This device can also be supplied in wafer form. Please contact your local Atmel sales office for detailed ordering information and minimum quantities. 2. Pb-free packaging alternative 3. See Figure 131 on page 293 and Figure 132 on page 293. Package Type 32A 32-lead, Thin (1.0 mm) Plastic Quad Flat Package (TQFP) 28P3 28-lead, 0.300" Wide, Plastic Dual Inline Package (PDIP) 32M1-A 32-pad, 5 x 5 x 1.0 body, Lead Pitch 0.50 mm Micro Lead Frame Package (MLF) 16 ATmega48/88/168 2545DS-AVR-07/04 ATmega48/88/168 Packaging Information 32A PIN 1 B PIN 1 IDENTIFIER E1 e E D1 D C 0~7 A1 A2 A L COMMON DIMENSIONS (Unit of Measure = mm) Notes: 1. This package conforms to JEDEC reference MS-026, Variation ABA. 2. Dimensions D1 and E1 do not include mold protrusion. Allowable protrusion is 0.25 mm per side. Dimensions D1 and E1 are maximum plastic body size dimensions including mold mismatch. 3. Lead coplanarity is 0.10 mm maximum. SYMBOL MIN NOM MAX A - - 1.20 A1 0.05 - 0.15 A2 0.95 1.00 1.05 D 8.75 9.00 9.25 D1 6.90 7.00 7.10 E 8.75 9.00 9.25 E1 6.90 7.00 7.10 B 0.30 - 0.45 C 0.09 - 0.20 L 0.45 - 0.75 e NOTE Note 2 Note 2 0.80 TYP 10/5/2001 R 2325 Orchard Parkway San Jose, CA 95131 TITLE 32A, 32-lead, 7 x 7 mm Body Size, 1.0 mm Body Thickness, 0.8 mm Lead Pitch, Thin Profile Plastic Quad Flat Package (TQFP) DRAWING NO. REV. 32A B 17 2545DS-AVR-07/04 28P3 D PIN 1 E1 A SEATING PLANE L B2 B1 A1 B (4 PLACES) 0 ~ 15 REF e E C COMMON DIMENSIONS (Unit of Measure = mm) eB Note: 1. Dimensions D and E1 do not include mold Flash or Protrusion. Mold Flash or Protrusion shall not exceed 0.25 mm (0.010"). MIN NOM MAX - - 4.5724 A1 0.508 - - D 34.544 - 34.798 E 7.620 - 8.255 E1 7.112 - 7.493 B 0.381 - 0.533 B1 1.143 - 1.397 B2 0.762 - 1.143 L 3.175 - 3.429 C 0.203 - 0.356 eB - - 10.160 SYMBOL A e NOTE Note 1 Note 1 2.540 TYP 09/28/01 R 18 2325 Orchard Parkway San Jose, CA 95131 TITLE 28P3, 28-lead (0.300"/7.62 mm Wide) Plastic Dual Inline Package (PDIP) DRAWING NO. 28P3 REV. B ATmega48/88/168 2545DS-AVR-07/04 ATmega48/88/168 32M1-A D D1 1 2 3 0 Pin 1 ID E1 SIDE VIEW E TOP VIEW A3 A2 A1 A 0.08 C P COMMON DIMENSIONS (Unit of Measure = mm) D2 Pin 1 ID 1 2 3 P E2 SYMBOL MIN NOM MAX A 0.80 0.90 1.00 A1 - 0.02 0.05 A2 - 0.65 1.00 A3 b 0.20 REF 0.18 D L D2 3.25 4.75BSC 2.95 e Notes: 1. JEDEC Standard MO-220, Fig. 2 (Anvil Singulation), VHHD-2. 3.10 5.00 BSC E1 E2 0.30 4.75 BSC 2.95 E BOTTOM VIEW 0.23 5.00 BSC D1 e b NOTE 3.10 3.25 0.50 BSC L 0.30 0.40 0.50 P - - 0 - - 0.60 12o 01/15/03 R 2325 Orchard Parkway San Jose, CA 95131 TITLE 32M1-A, 32-pad, 5 x 5 x 1.0 mm Body, Lead Pitch 0.50 mm Micro Lead Frame Package (MLF) DRAWING NO. 32M1-A REV. C 19 2545DS-AVR-07/04 Errata ATmega48 The revision letter in this section refers to the revision of the ATmega48 device. Rev A * * * * * Wrong values read after Erase Only operation Watchdog Timer Interrupt disabled Start-up time with Crystal Oscillator is higher than expected High Power Consumption in Power-down with External Clock Asynchronous Oscillator does not stop in Power-down 1. Wrong values read after Erase Only operation At supply voltages below 2.7 V, an EEPROM location that is erased by the Erase Only operation may read as programmed (0x00). Problem Fix/Workaround If it is necessary to read an EEPROM location after Erase Only, use an Atomic Write operation with 0xFF as data in order to erase a location. In any case, the Write Only operation can be used as intended. Thus no special considerations are needed as long as the erased location is not read before it is programmed. 2. Watchdog Timer Interrupt disabled If the watchdog timer interrupt flag is not cleared before a new timeout occurs, the watchdog will be disabled, and the interrupt flag will automatically be cleared. This is only applicable in interrupt only mode. If the Watchdog is configured to reset the device in the watchdog time-out following an interrupt, the device works correctly. Problem fix / Workaround Make sure there is enough time to always service the first timeout event before a new watchdog timeout occurs. This is done by selecting a long enough time-out period. 3. Start-up time with Crystal Oscillator is higher than expected The clock counting part of the start-up time is about 2 times higher than expected for all start-up periods when running on an external Crystal. This applies only when waking up by reset. Wake-up from power down is not affected. For most settings, the clock counting parts is a small fraction of the overall start-up time, and thus, the problem can be ignored. The exception is when using a very low frequency crystal like for instance a 32 kHz clock crystal. Problem fix / Workaround No known workaround. 4. High Power Consumption in Power-down with External Clock The power consumption in power down with an active external clock is about 10 times higher than when using internal RC or external oscillators. Problem fix / Workaround Stop the external clock when the device is in power down. 5. Asynchronous Oscillator does not stop in Power-down The Asynchronous oscillator does not stop when entering power down mode. This leads to higher power consumption than expected. Problem fix / Workaround Manually disable the asynchronous timer before entering power down. 20 ATmega48/88/168 2545DS-AVR-07/04 ATmega48/88/168 Errata ATmega88 The revision letter in this section refers to the revision of the ATmega88 device. Rev. A * Writing to EEPROM does not work at low Operating Voltages * Part may hang in reset 1. Writing to EEPROM does not work at low operating voltages Writing to the EEPROM does not work at low voltages. Problem Fix/Workaround Do not write the EEPROM at voltages below 4.5 Volts. This will be corrected in rev. B. 2. Part may hang in reset Some parts may get stuck in a reset state when a reset signal is applied when the internal reset state-machine is in a specific state. The internal reset state-machine is in this state for approximately 10 ns immediately before the part wakes up after a reset, and in a 10 ns window when altering the system clock prescaler. The problem is most often seen during In-System Programming of the device. There are theoretical possibilities of this happening also in run-mode. The following three cases can trigger the device to get stuck in a reset-state: - Two succeeding resets are applied where the second reset occurs in the 10ns window before the device is out of the reset-state caused by the first reset. - A reset is applied in a 10 ns window while the system clock prescaler value is updated by software. - Leaving SPI-programming mode generates an internal reset signal that can trigger this case. The two first cases can occur during normal operating mode, while the last case occurs only during programming of the device. Problem Fix/Workaround The first case can be avoided during run-mode by ensuring that only one reset source is active. If an external reset push button is used, the reset start-up time should be selected such that the reset line is fully debounced during the start-up time. The second case can be avoided by not using the system clock prescaler. The third case occurs during In-System programming only. It is most frequently seen when using the internal RC at maximum frequency. If the device gets stuck in the reset-state, turn power off, then on again to get the device out of this state. 21 2545DS-AVR-07/04 Errata ATmega168 The revision letter in this section refers to the revision of the ATmega168 device. Rev A * Wrong values read after Erase Only operation * Part may hang in reset 1. Wrong values read after Erase Only operation At supply voltages below 2.7 V, an EEPROM location that is erased by the Erase Only operation may read as programmed (0x00). Problem Fix/Workaround If it is necessary to read an EEPROM location after Erase Only, use an Atomic Write operation with 0xFF as data in order to erase a location. In any case, the Write Only operation can be used as intended. Thus no special considerations are needed as long as the erased location is not read before it is programmed. 2. Part may hang in reset Some parts may get stuck in a reset state when a reset signal is applied when the internal reset state-machine is in a specific state. The internal reset state-machine is in this state for approximately 10 ns immediately before the part wakes up after a reset, and in a 10 ns window when altering the system clock prescaler. The problem is most often seen during In-System Programming of the device. There are theoretical possibilities of this happening also in run-mode. The following three cases can trigger the device to get stuck in a reset-state: - Two succeeding resets are applied where the second reset occurs in the 10ns window before the device is out of the reset-state caused by the first reset. - A reset is applied in a 10 ns window while the system clock prescaler value is updated by software. - Leaving SPI-programming mode generates an internal reset signal that can trigger this case. The two first cases can occur during normal operating mode, while the last case occurs only during programming of the device. Problem Fix/Workaround The first case can be avoided during run-mode by ensuring that only one reset source is active. If an external reset push button is used, the reset start-up time should be selected such that the reset line is fully debounced during the start-up time. The second case can be avoided by not using the system clock prescaler. The third case occurs during In-System programming only. It is most frequently seen when using the internal RC at maximum frequency. If the device gets stuck in the reset-state, turn power off, then on again to get the device out of this state. 22 ATmega48/88/168 2545DS-AVR-07/04 ATmega48/88/168 Datasheet Change Log Changes from Rev. 2545C-04/04 to Rev. 2545D-07/04 Please note that the referring page numbers in this section are referred to this document. The referring revision in this section are referring to the document revision. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Changes from Rev. 2545B-01/04 to Rev. 2545C-04/04 1. 2. 3. 4. Changes from Rev. 2545A-09/03 to Rev. 2545B-01/04 1. 2. 3. 4. 5. 6. 7. 8. 9. Updated instructions used with WDTCSR in relevant code examples. Updated Table 8 on page 28, Table 21 on page 43, Table 112 on page 269, Table 114 on page 269, and Table 131 on page 288. Updated "System Clock Prescaler" on page 33. Moved "Timer/Counter2 Interrupt Mask Register - TIMSK2" and "Timer/Counter2 Interrupt Flag Register - TIFR2" to "8-bit Timer/Counter Register Description" on page 143. Updated cross-reference in "Electrical Interconnection" on page 199. Updated equation in "Bit Rate Generator Unit" on page 204. Added "Page Size" on page 274. Updated "Serial Programming Algorithm" on page 287. Updated "Ordering Information" for "ATmega168" on page 16 Updated "Errata ATmega88" on page 21 and "Errata ATmega168" on page 22. Speed Grades changed: - 12MHz to 10MHz - 24MHz to 20MHz Updated "Maximum Speed vs. VCC" on page 293. Updated "Ordering Information" on page 14. Updated "Errata ATmega88" on page 21. Added PDIP to "I/O and Packages", updated "Speed Grade" and Power Consumption Estimates in "Features" on page 1. Updated "Stack Pointer" on page 11 with RAMEND as recommended Stack Pointer value. Added section "Power Reduction Register" on page 37 and a note regarding the use of the PRR bits to 2-wire, Timer/Counters, USART, Analog Comparator and ADC sections. Updated "Watchdog Timer" on page 46. Updated Figure 55 on page 125 and Table 56 on page 126. Extra Compare Match Interrupt OCF2B added to features in section "8bit Timer/Counter2 with PWM and Asynchronous Operation" on page 132 Updated Table 19 on page 37, Table 102 on page 245, Table 118 to Table 121 on page 272 to 273 and Table 98 on page 236. Added note 2 to Table 115 on page 270. Fixed typo in Table 42 on page 81. Updated whole "ATmega48/88/168 Typical Characteristics - Preliminary Data" on page 298. Added item 2 to 5 in "Errata ATmega48" on page 20. 23 2545DS-AVR-07/04 10. 11. 12. 24 Renamed the following bits: - SPMEN to SELFPRGEN - PSR2 to PSRASY - PSR10 to PSRSYNC - Watchdog Reset to Watchdog System Reset Updated C code examples containing old IAR syntax. Updated BLBSET description in "Store Program Memory Control and Status Register - SPMCSR" on page 260. 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