Rev 1; 5/08 DS28DG02 Evaluation Board/Evaluation System The DS28DG02 evaluation system (EV system) consists of an evaluation board (EV board) and a Maxim CMAXQUSB command module. The EV board is a daughter card for the command module. PC connectivity is included in the kit and free evaluation software is available for download from the web page listed in Support Resources. The DS28DG02 is a mixed-signal memory device. It contains 2Kb of EEPROM memory, along with PIO, real-time clock (RTC), reset, battery monitor, and watchdog functions. Communication to the device is through the industry-standard Serial Peripheral Interface (SPITM) interface. The evaluation software runs under 32-bit Windows Vista(R), XP, 2000, and 98SE operating systems, providing a handy user interface to exercise the DS28DG02 features. Features Proven PCB Layout Complete Evaluation System Convenient On-Board Test Points Easy Setup PC Connectivity Included Free Downloadable Evaluation Software Available Ordering Information PART TYPE DS28DG02EVKIT EV Kit Support Resources 1) DS28DG02 EV Kit Data Sheet and Software: www.maxim-ic.com/DS28DG02EVKit EV Kit Contents DESIGNATION QTY 2) User's Guide to the DS28DG02: www.maxim-ic.com/AN4040 H1 4 2-pin shunts (for jumpering) Tyco/Amp 881545-2 3) Application Note 3601: Troubleshooting Windows Plug-and-Play and USB for Maxim Evaluation Kits: www.maxim-ic.com/AN3601 H2 1 Small antistatic bag to hold H1 shunts H3 1 DS28DG02 EV board H4 1 Small antistatic bag to hold EV board H5 1 Instruction sheet H6 1 Box and packaging material to hold bagged EV board, bag of shunts, and instruction sheet (H1-H5) H7 1 Boxed CMAXQUSB command module with USB cable H8 1 Box and packaging material to hold EV kit contents (H1-H7) 4) Listing of All Multifunction Memory EV Kits: www.maxim-ic.com/memoryEVKits 5) Technical Support: www.maxim-ic.com/support DESCRIPTION SPI is a trademark of Motorola, Inc. Windows Vista is a registered trademark of Microsoft Corp. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com. 1 Evaluates: DS28DG02 General Description Evaluates: DS28DG02 DS28DG02 Evaluation Board/Evaluation System Component List DESIGNATION QTY B1 1 2 DESCRIPTION SUPPLIER/PART NUMBER 3V lithium 16mm coin battery with solderable tabs Panasonic BR1632A/HA C1, C2 2 0.1F SMT capacitors (1206) KMET C1206C104K1RACTU D1, D6, D7 3 SMT red LEDs (1206) LiteOn LTST-C150CKT D2-D5 4 SMT green LEDs (1206) LiteOn LTST-C150GKT J1 1 100-mil centers, square-post, 2-pin terminal strip Molex 22-28-4022 J2 1 100-mil centers, 40-pin (dual-row) female, right-angle header Available from the following suppliers: Methode (Adam Tech) RS2R-40-G Oupiin 2044-2X20GRSN Samtec SSW-120-02-S-D-RA J3-J4 2 100-mil centers, square-post, 3-pin terminal strip Molex 22-28-4032 J6 1 100-mil centers, square-post, 12-pin terminal strip right angle Molex 22-28-8120 R1 1 SMT 500 1% resistor (1206) ROHM MCR18EZHF4990 R2 1 100 mechanical potentiometer through-mount, 3-pin Available from the following suppliers: Copal Electronics CT6EP101 Murata PVC6A101C01B00 R3, R8, R9 3 10k resistors (1206) Panasonic-ECG ERJ-8ENF1002V R5 1 Through-mount, 3-pin 500 mechanical potentiometer Available from the following suppliers: Copal Electronics CT6EP501 Murata PVC6A501C01B00 R6 1 SMT 250 1% resistor (1206) ROHM MCR18EZHF2490 R7 1 SMT 470 resistor (1206) Panasonic-ECG ERJ-8ENF4700V RP1 1 1k resistor pack, 9 res, 10-pin CTS Corporation 770101102P RP2 1 100k resistor pack, 9 res, 10-pin CTS Corporation 770101104P RP3 1 470 resistor pack, 9 res, 10-pin CTS Corporation 770101471P SB1 1 Jumper block with 8 built-in switches, 16-pin DIP Grayhill Incorporated 76SB08ST SW1 1 Momentary pushbutton switch Panasonic-ECG EVQ-PJA04Q TP1, TP2 2 Test points Keystone 5011 U1 1 2Kb SPI EEPROM with PIO, RTC, reset, battery monitor and watchdog (4.4mm 28-pin TSSOP) Maxim DS28DG02E-3C+ X1 1 32kHz time crystal Citizen CFS145-32.768KDZF-UB _______________________________________________________________________________________ DS28DG02 Evaluation Board/Evaluation System Evaluates: DS28DG02 Figure 1. DS28DG02 EV Board Figure 2. DS28DG02 EV Board Connected to CMAXQUSB _______________________________________________________________________________________ 3 Evaluates: DS28DG02 DS28DG02 Evaluation Board/Evaluation System Quick Start Note: In the following sections software-related items are identified by bolding. Text in bold refers to items directly from the EV kit software. Items in bold and underline refer to items from the Windows operating system. 1) Before beginning, make sure the following equipment is available: * DS28DG02 (contains DS28DG02 EV board and CMAXQUSB module). * Computer with a Windows Vista/XP/2000/98SE operating system with a spare USB port. 2) Do the following before connecting to the PC: * Select 3.3V logic by setting the CMAXQUSB VDD SELECT jumper. * Set up the EV board by placing a jumper on the J3 jumper block (J3 BATT SRC). If you wish to evaluate the battery monitor function, choose VCC to prevent the battery from prematurely draining. Also, place a jumper on the J1 RESET ENABLE pins, along with a jumper on J4 WPZ INPUT (preferably in the rightmost position to prevent accidental write protection of the SPI Status Byte). * Connect the EV board to the CMAXQUSB board with the 40-pin connector at location P4 (the SPI pins). See Figure 2 for proper EV board orientation (component side up) when connecting the EV board to the CMAXQUSB board. 3) Download the evaluation software from the EV kit's Quick View: www.maxim-ic.com/DS28DG02EVKit. The evaluation software is provided as a *.zip archive file. Unzip the archive's contents into an empty or newly created directory. 4) Connect the USB cable between the CMAXQUSB and the computer. When you plug in the CMAXQUSB board for the first time, the Windows plug-and-play system detects the new hardware and automatically runs the Add New Hardware Wizard. Be sure to specify the search location for the device driver, which is the directory where the evaluation software files were unzipped. 5) During device driver installation, Windows displays a warning message indicating that the device driver for the CMAXQUSB board does not contain a digital signature. This is not an error condition. It is safe to proceed with the installation. 6) If any problems occur during device driver installation, refer to Application Note 3601: Troubleshooting Windows Plug-and-Play and USB for Maxim Evaluation Kits for more details. 4 7) The Microsoft .NET framework Version 1.1 is required for the program to run. To verify if it is installed, look in Control Panel under Add/Remove Software for a listing. If no listing is found, go to www.microsoft.com and perform a site search for .NET 1.1 redistributable. Click on the first item in the results list. It should contain download and installation instructions. 8) Start the EV kit software by double-clicking the file, DS28DG02_Evaluation_Program.exe, in the file folder containing the unzipped evaluation software files. Detailed Description of Software Figure 3 shows the DS28DG02 software program's main window. Note that it consists of seven tabs, with each tab offering the ability to exercise a group of related DS28DG02 functional blocks. The sections are: SPI, R/W, UserEE, MFC/MFS, GPIO, RTC, and WatchDog. Each of these tabs is described in this section. Note that a status pane exists at the very bottom of the window. The left-hand side gives the firmware string of the CMAXQUSB board (if connected), and the righthand side gives status information (in the form of a small string) on the success or failure of the last operation attempted. SPI See Figure 3 for a screenshot of the SPI tab. This tab allows the user to input raw SPI commands and communicate to the DS28DG02 through this low-level serial protocol. The user can assert the chip select (CS) pin to enable communication to the device, and send data to the chip by inputting data into the master-out, slavein (MOSI) text box and clicking the Execute SPI Comm button. MOSI is also read out from the chip during the data exchange. R/W Figure 4 shows a screenshot of the R/W tab. This tab exercises raw read and write functions. Be careful using this tab as the reading/writing extends to PIO and control/status registers. To use, simply give the starting address from which to perform the memory operation and the number of bytes to read or write. If performing a write operation, input the data to write in hexadecimal form (with a space between bytes) in the text box. Next, choose the type of operation (Read Op or Write Op), and click the Execute Memory Op button to perform the action. For reading and writing the user EEPROM areas, see the UserEE section. _______________________________________________________________________________________ DS28DG02 Evaluation Board/Evaluation System Evaluates: DS28DG02 Figure 3. DS28DG02 Evaluation Software: Main Window Figure 4. DS28DG02 Evaluation Software: R/W Tab _______________________________________________________________________________________ 5 Evaluates: DS28DG02 DS28DG02 Evaluation Board/Evaluation System Figure 5. DS28DG02 Evaluation Software: UserEE Tab UserEE Figure 5 shows the UserEE tab. It allows a safe way to read and write to the user EEPROM memory areas of the DS28DG02. To use, first input which 64-byte block of EEPROM memory is read or written into the General Memory Block spin box. Valid numbers are 0, 1, 2, or 3. Next, choose the format type of the data to be displayed in the text box after a read operation or inputted 6 before a write operation. The choices are ASCII or hex. Finally, choose which memory operation is desired by clicking on either the Read User EEPROM or Write User EEPROM buttons. Prior to writing to the part, make sure the data to write has been successfully entered into the text box in the correct format, either ASCII (no spaces) or hex (space between each byte). _______________________________________________________________________________________ DS28DG02 Evaluation Board/Evaluation System Evaluates: DS28DG02 Figure 6. DS28DG02 Evaluation Software: MFC/MFS Tab MFC/MFS The MFC/MFS tab allows the user to read the status register for alarms and flags and write to the control register to enable the various monitors and timers and change other hardware settings. It also allows for exercising the SPI status register, which gives status on blocks of EEPROM memory that are write protected and specifies the duration of the watchdog timeout. See Figure 6 for a screenshot. This tab is used extensively when experimenting with nonmemory functions of the DS28DG02, such as voltage monitor, watchdog, write protect, and RTC functions. To use the tab, start by reading the registers to see which flags and alarms have been set. Clicking the Read MFC/MFS button and the Read button in the SPI Status Byte section retrieves them. Once all the flags, alarms, and settings have been retrieved, the DS28DG02 can be reconfigured to the desired settings and any alarm conditions can be cleared. _______________________________________________________________________________________ 7 Evaluates: DS28DG02 DS28DG02 Evaluation Board/Evaluation System The MFC/MFS tab is divided into two sections: the Multifunction Registers section and the SPI Status Byte section. In the Multifunction Registers section, the left-hand side of the tab shows the control register's settings. To set these, just click in the checkbox next to the appropriate label. The last setting does not contain a checkbox, but rather, a listbox of four settings for the battery trip point (BTRP). Highlight the desired BTRP setting by clicking on it. See Table 1 for a list of control settings. Clicking on the MFC settings automatically writes the new setting to the part. A checkmark means a 1 has been written to the register bit, enabling the fea- ture, and no checkmark means that a 0 has been written to the register bit, disabling the feature. The BTRP has four possible settings (requiring 2 bits). See Table 1 for a list of the possible battery monitor trip points. An alternate way to change the control register settings (besides clicking the checkboxes) is to calculate the byte value in hex of the control register, which consists of a single byte. See the BITS column of Table 1, keeping in mind a check is a 1 and an uncheck is a 0. After calculating this number, input it into the Control text box and click the Write MFC button. Table 1. Control Register Settings SETTING BITS DEFINITION CAE: Clock Alarm Enable b0 Enable/disable control of the RTC/calendar alarm. check: enable uncheck: disable (power-on default) OSCE: RTC Oscillator Enable b1 Run/halt control of the RTC's 32kHz oscillator. check: enable uncheck: disable (power-on default) WDE: Watchdog Enable b2 Enable/disable control of the watchdog and its alarm. check: enable uncheck: disable (power-on default) WDOS: Watchdog Output Selection b3 Pin selection for watchdog alarm signaling. check: ALMZ pin (lights red D6 LED) uncheck: WDOZ pin (lights red D7 LED) (power-on default) BTRP: Battery Monitor Trip Point b[5:4] Selection of the nominal BTRP voltage. Select one of the following: b00 1.75V (power-on default) b01 2.00V b10 2.25V b11 2.50V Enable/disable control of the battery monitor and its alarm. check: enable uncheck: disable (power-on default) BME: Battery Monitor Enable 8 b6 Notes: 1. The battery test takes place: a) after BME changes to 1 b) after VCC ramps up c) every hour on the hour 2. The RTC must be running (OSCE enabled) for the battery monitor to function. _______________________________________________________________________________________ DS28DG02 Evaluation Board/Evaluation System trol and status registers, it is not memory mapped and can only be updated through SPI instructions. It holds several bits that control an elaborate scheme to prevent inadvertent changes of data stored in the device. Complete details of this scheme can be found in the DS28DG02's data sheet in the Principles of Operation section. See Table 3 for a listing of the SPI Status Byte settings. To read these status/control bits, click on the Read button. There are two ways to write to the register. The first is to click on the checkboxes by the desired settings to be activated. Placing a checkmark in the boxes enables/activates the setting. This is equivalent to adding a 1 in the bit field. Unchecking the boxes deactivates/disables the settings. This is equivalent to adding a 0 in the bit field. Any mouse click on a checkbox writes immediately to the part. The second method of writing entails calculating the byte value in hex of the register. See the BITS column of Table 3 for which bit position goes with which setting. After calculating the byte value, input the resulting hex number into the Status text box and click the Write button. Table 2. Status Register Alarms and Status Flags ALARM/FLAG BITS DEFINITION RSTF: Reset Flag b0 RSTZ pin activity indicator; set whenever there is a pulse at RSTZ. VCC ramp up: 1; VBAT attach: 0 WDA: Watchdog Alarm b1 Watchdog alarm indicator; set whenever the watchdog is enabled and the watchdog timer expires. VCC ramp up: 0; VBAT attach: 0 CLKA: Clock Alarm b2 RTC/calendar alarm indicator; set whenever the clock alarm is enabled and RTC and RTC alarm register match. VCC ramp up: 0; VBAT attach: 0 BORF: Battery-On Reset Flag b3 Battery attach indicator; set whenever the voltage at VBAT ramps up above VBATmin. VCC ramp up: not affected; VBAT attach: 1 PORF: Power-On Reset Flag b4 Power-on reset indicator; set whenever the voltage at VCC ramps up above VCCmin. VCC ramp up: 1; VBAT attach: 0 WPZV: Hardware Write-Protect Value b5 WPZ pin state readout; reports the logic state at the WPZ pin. VCC ramp up: WPZ pin state; VBAT attach: not affected BATA: Battery Alarm b6 Low battery indicator; set whenever the battery alarm is enabled and if, during a battery test, VBAT is below the selected VBAT trip point. VCC ramp up: battery test if BME = 1; VBAT attach: 0 _______________________________________________________________________________________ 9 Evaluates: DS28DG02 The other half of the Multifunction Registers section of the MFC/MFS tab consists of the DS28DG02's status register. Similar to the control register, a list of checkboxes are listed. A checkmark means an alarm or flag is set or active (giving a 1) and no checkmark means that the alarm or flag is not active (giving a 0). See Table 2 for a list of status register alarms and status flags. As with the control register, the status register is a single byte, with individual alarms and status flags taking up single bits. So, clicking on the Read MFC/MFS button gives a hex number representing the entire status byte. This number is displayed in the Status text box. Translating this number to binary gives the indvidual alarms/flags of the status register. See the BITS column in Table 2 for the bit designator. Note that writing to the control register, except for the WPZV status flag, clears all alarms/flags, and that when an alarm or flag is set, the MFC/MFS tab displays a checkmark in the appropriate alarm/flag checkbox. The second section of the MFC/MFS software tab is the SPI Status Byte. This byte register contains control bits and two read-only status bits. Unlike the other con- Evaluates: DS28DG02 DS28DG02 Evaluation Board/Evaluation System Table 3. SPI Status Register SETTING RDYZ: Ready (Read-Only Bit) WEN: Write Enabled (Read-Only Bit) BITS DEFINITION b0 Indicates whether an EEPROM write cycle is in progress. check: write cycle in progress uncheck: ready (normal state) b1 Indicates whether the device accepts a WRITE instruction; set through the WREN instruction; cleared through the WRDI instruction or completion of a valid WRITE or a valid WRSR instruction. Refer to the data sheet for definitions of WREN, WRDI, and WRSR. check: write enabled (power-on default) uncheck: write enabled These bits specify which of the four user-memory blocks are write protected (independent of WPEN and WPZ). Here 1 means checked and 0 means unchecked. BP[1:0]: Block Write Protect b[3:2] Settings: 00b not protected (factory default) 01b block 3 (0C0h to 0FFh) protected 10b blocks 2 and 3 (080h to 0FFh) protected 11b blocks 0 to 3 (000h to 0FFh) protected These bits specify the duration of the watchdog timeout if the watchdog is enabled (WDE at address 134h = 1). WD[1:0]: Watchdog Timeout RPROT: Register Protection WPEN: Hardware WriteProtect Enable 10 b[5:4] Settings: 00b 1.64s (factory default) 01b 820ms 10b 410ms 11b 200ms These are nominal values. For tolerances, refer to the Electrical Characteristics in the DS28DG02 data sheet. b6 Specifies whether the writeable addresses in the range of 120h and higher are write protected (independent of WPEN and WPZ). check: protected uncheck: not protected (factory default) b7 Specifies whether b7:b2 of the SPI status register (nonvolatile bits) are writeable or whether the WPZ pin state controls the write protection. check: protection controlled by WPZ pin state If WPEN = 1 and WPZ pin state is 0 the SPI status register is write protected and a WRSR instruction is not valid. uncheck: writable (factory default) ______________________________________________________________________________________ DS28DG02 Evaluation Board/Evaluation System pins is a logic 0. So, the checkmarks in Figure 7 would indicate the LEDs are not lit. Unchecking them would light the LEDs. The second section of the GPIO tab is labeled Direction. Each pin can be either an input pin or an output pin. A checkmark (logic 1) by the pin number indicates the pin is configured as an input. Unchecking the pin configures it as an output. Figure 7 shows the first eight pins configured as input and the rest as output. The Inversion Mask is the third section of the GPIO tab. When a pin is checked under this section, the inverse of the state of the pin displays in the Input Value section. It does not affect the actual state of the pin, just the read-out. Finally, the Input Value is the fourth section of the GPIO tab. It shows the state of the pin with inversion mask (if any) applied. Note that this is read-only and the checkboxes cannot be changed. Note that all four sections contain checkboxes indicating each PIO pin by number. To write to each section's register, simply click on the checkbox by the pin number. This action toggles the value and write the change to the part immediately. There is also an alternate way to write to the PIO registers. On the GPIO tab, three of the four sections corresponding to the appropriate register have Figure 7. DS28DG02 Evaluation Software: GPIO Tab ______________________________________________________________________________________ 11 Evaluates: DS28DG02 GPIO Figure 7 shows the GPIO tab. Note that it consists of four sections, each containing 12 checkboxes correlating to the 12 PIO pins of the DS28DG02. The EV board was designed so that the first eight pins are input pins. An 8-switch DIP switch block is provided to allow changing the input states from 0 to 1 or vice versa. If the user toggles a switch, clicking the Read All button on the GPIO software tab shows the change. Conversely, the last four pins (pins 8-11) of the EV board were designed to be used as outputs. Each output is associated with a green LED that responds to changes of state of the output pin. The last four pins can be switched on through software interaction, specifically by clicking on the checkboxes labeled 8, 9, 10, and 11. The results show up on the EV board as LEDs being turned on or off. Under Output Value, Figure 7 shows the first eight pins in the off or logic 0 state. For the EV board it does not matter that these checkboxes are on or off because the board uses the pins as inputs, so output values are meaningless in this situation. For more information about the DS28DG02's PIO schematic, see Figure 10. Conversely, the last four pins under Output Value of the GPIO tab are checked and are configured on the EV board as outputs. A green LED lights when the output of one of the last four Evaluates: DS28DG02 DS28DG02 Evaluation Board/Evaluation System a text box located above the pin checkboxes. The text box is editable with a Write button underneath. This allows the user to calculate the desired PIO settings on a bit level, and input the resulting hex number to the text box. Click the Write button and the specific PIO register changes accordingly. The GPIO software tab contains two buttons to save and restore default PIO settings. One way to experiment with this is to set the DS28DG02's PIO pins to the desired states and/or settings and click the Save As Default button. This saves the settings to the DS28DG02. Next, change the settings and click the Reload Defaults button. This restores the previous PIO settings. has been entered into the text boxes to the DS28DG02's RTC. The third button is labeled Sync RTC to PC, and when clicked, reads the PC's clock and writes the resulting time/date info to the DS28DG02's time registers. RTC Note that the RTC and the RTC alarm must be enabled prior to experimenting with the RTC tab. Enabling and disabling the RTC and RTC alarm and clearing any resulting alarm conditions are done on the MFC/MFS software tab. To enable the RTC, check the box labeled OSCE (oscillator enable). To enable the RTC alarm, check the box labeled CAE (clock alarm enable). To clear any resulting alarm condition that lights the red ALMZ LED, click the Clear MFS button. The red ALMZ LED then turns off. See Figure 8 for a screenshot of the RTC tab. This tab allows for exercising and configuring the DS28DG02's RTC. It presents two sections. The top section is labeled Real-Time Clock and contains text boxes to input the time, date, and 24-hour time settings. Three buttons are also located in this section. The Read RTC and Write RTC buttons read the RTC, displaying the time/date in the appropriate text boxes, or write what The bottom section of the RTC tab is labeled RTC Alarm. This section contains two buttons, one for reading the alarm and one for writing the alarm. The alarm settings can either be input or read into the text boxes located in this section. The text boxes include the alarm occurrence frequency (every second, minute, hour, day, week, or month). They also allow the user to input the time, date, or day associated with the alarm. When the clock alarms, the red ALMZ LED lights on the EV board. Figure 8. DS28DG02 Evaluation Software: RTC Tab 12 ______________________________________________________________________________________ DS28DG02 Evaluation Board/Evaluation System Additional setup of the DS28DG02 is required prior to experimenting with the watchdog feature of the DS28DG02. First, the user must enable some options located on the MFC/MFS software tab. Specifically, the user must check the oscillator enable (OSCE) and watchdog enable (WDE) checkboxes. These settings are part of the control register. Optionally, select the desired output pin for the watchdog alarm. It can alarm on either the WDOZ pin or the ALMZ pin. When alarming, either pin lights up the appropriate LED on the EV board. The last items to set up for watchdog functionality are the WD1 and WD0 checkboxes under the SPI Status Byte section of the MFC/MFS software tab. These specify the duration of the watchdog timeout. See Table 4 for the watchdog timeout settings. Note that the WDI pin of the DS28DG02 can be floating when the EV board is first connected to the CMAXQUSB command module. Either grounding this pin or selecting the WatchDog tab of the software and starting the watchdog signal on this pin defines the state of the pin and allows further experimentation. Table 4. Watchdog Timeout Settings WD1 WD0 TIMEOUT (ms) Unchecked Unchecked 1600 Unchecked Checked 800 Checked Unchecked 400 Checked Checked 200 Note: These are nominal timeout values. Check the DS28DG02 data sheet's Electrical Characteristics table for complete ranges. Detailed Description of Hardware Figure 9 is a visual overview of the hardware sections of the DS28DG02 EV board. Many of the components and their use are described in previous sections of this document, so this section describes the components not previously mentioned. VBAT Monitoring A battery can be connected to the DS28DG02 that supplies power to the RTC and associated registers if VCC is switched off. Because of this, the DS28DG02 was designed with a built-in battery monitor. If the battery voltage falls below a user-selected trip point monitored on the VBAT pin, the DS28DG02 outputs an alarm. On the EV board, the alarm lights up the red ALMZ LED. To exercise the battery monitor on the EV board, first place a jumper on the correct pins of J3. Jumper J3 allows the user to choose how the V BAT pin of the DS28DG02 receives power, either through the onboard battery or through VCC (powered by the PC's USB port). Place the jumper on the side of J3 labeled VCC (leaving the jumper on BATT would prematurely deplete the battery). Once that has been done, use the software described in the Detailed Description of Software section to enable the clock oscillator. Click on the MFC/MFS tab and check the oscillator enable (OSCE) checkbox. The battery monitor enable (BME) checkbox should be checked along with selecting a battery trip point (BTRP). See Figure 6 for the BTRP selections, which are 1.75V, 2.00V, 2.25V, and 2.50V. Just select the desired setting by clicking on it. Finally, adjust the potentiometer R5 to a low value and rewind the RTC to a few seconds before hour rollover as the battery monitor tests the VBAT voltage every hour on the hour. The RTC can be set on the EV board through the RTC software tab. See Figure 8 for a screenshot. The alarm shows on the EV board by lighting the red ALMZ LED. It shows on the MFC/MFS software tab as well. Click the Read MFC/MFS button, and the battery alarm (BATA) checkbox is checked. To clear the alarm, click the Clear MFS button. This switches off the ALMZ LED. ______________________________________________________________________________________ 13 Evaluates: DS28DG02 WatchDog The WatchDog tab of the EV software provides a way to exercise the DS28DG02's watchdog. This tab simply provides the option to select the watchdog input (WDI) pin's input frequency. The software provides the watchdog signal's frequency to the WDI pin based upon the user input on this tab. At least one input is outside any of the watchdog timeout settings. Evaluates: DS28DG02 DS28DG02 Evaluation Board/Evaluation System * GROUND TEST POINTS (TP1 AND TP2) * ALMZ AND WDOZ PINS (RED LEDs) * PIO 8-11 GREEN OUTPUT INDICATOR LEDs * RSTZ PIN (RED LED) * J1 RESET-ENABLE JUMPER * J4 WPZ WRITE-PROTECT PIN JUMPER * R2 VCC INPUT POTENTIOMETER * SW1 RESET BUTTON * B1 3V LITHIUM CELL * R5 VBAT INPUT POTENTIOMETER * J3 VBAT SOURCE JUMPER (CHOOSE BETWEEN BATTERY AND VCC) * GPIO EXPERIMENTER'S HEADER * GPIO INPUT DIP SWITCH * DS28DG02 * 32kHz CRYSTAL Figure 9. DS28DG02 EV Board Component Map 14 ______________________________________________________________________________________ DS28DG02 Evaluation Board/Evaluation System The reset monitor of the DS28DG02 generates a reset to the CPU if the voltage at the VCC pin falls below the factory-set limit, which is between 2.97V and 3.14V with the typical trip point falling at 3.05V. The reset output includes a debounce circuit for manual pushbutton reset. There are two methods to test reset monitoring of the DS28DG02. The first is to simply push the reset pushbutton switch labeled as SW1 on the EV board. Doing so briefly lights the EV board's red RSTZ LED; this is also indicated on the MFC/MFS software tab of the EV software by a checkmark in the reset flag (RSTF) checkbox. To see the flag, the MFC/MFS screen must be refreshed by clicking on the Read MFC/MFS button. To clear the flag, click on the Clear MFS button. The second method is by adjusting the R2 potentiometer on the EV board until the red RSTZ LED lights up. To do this, use a Phillips-head screwdriver and turn the potentiometer counterclockwise. Next, refresh the MFC/MFS software tab by clicking on the Read MFC/MFS button. A check should appear in the RSTF checkbox showing that the low voltage condition occurred. To clear the flag, turn the potentiometer clockwise until the light turns off and click on the Clear MFS button on the MFC/MFS software tab. Write Protection The DS28DG02 provides robust write protection for different sections of on-board memory. The first section of memory that has a write-protection scheme is the user EEPROM area. This area consists of four separate memory blocks of 64 bytes each. These can be write protected through the EV software's MFC/MFS tab specifically by clicking on the BP0 and BP1 checkboxes under the SPI Status Byte section. See Table 5 for the possible combinations of write protection available for user EEPROM block write protection. The second section of memory with a write-protection scheme is the block of memory addresses at 120h and higher. This block is protected through the register protection (RPROT) bit of the SPI Status Byte. This bit can be changed through software by clicking the RPROT checkbox on the EV software's MFC/MFS tab. A checkmark indicates that the addresses are write protected; no checkmark means that the addresses are writable. The RPROT checkbox write protects the MFS, MFC, and PIO registers. A valid experiment would be to place a checkmark in the RPROT checkbox, and try to read or write any of the registers that RPROT write protects. The attempts should be unsuccessful. Finally, the previously mentioned SPI Status Byte can be write protected. This is slightly more difficult to do since the bit to write protect the SPI Status Byte is actually a part of the SPI Status Byte. This was intentionally designed this way, as the SPI Status Byte is where all write-protection settings are located. The bit to set is the write-protect enable (WPEN) bit. On the MFC/MFS software tab, click the checkbox labeled WPEN to turn on write protection of the SPI Status Byte. Turning off write protection of the SPI Status Byte requires the WPZ pin of the DS28DG02 to be at a logic 1 state. When the WPZ pin is at the logic 1 state, the SPI Status Byte is writable even if WPEN is checked. Placing a jumper on the rightmost two pins of J4 of the EV board can set the WPZ pin to a logic 1, making an otherwise write-protected SPI Status Byte writable. Table 5. User EEPROM Write Protection with BP1 and BP0 BP1 BP0 PROTECTED MEMORY 0 0 Not protected (factory default) 0 1 Block 3 (0C0h to 0FFh) protected 1 0 Blocks 2 and 3 (080h to 0FFh) protected 1 1 Blocks 0 to 3 (000h to 0FFh) protected ______________________________________________________________________________________ 15 Evaluates: DS28DG02 Reset Monitoring (VCC Monitoring and Pushbutton Reset) 16 Figure 10. DS28DG02 EV Board Schematics ______________________________________________________________________________________ 1 2 3 J4 C2 0.1F WPZ WDOZ WDI RSTZ SO SCK VCC GND GND WPZ INPUT VCC CHIP J2 2 1 4 3 6 5 8 7 9 10 11 12 13 14 16 15 18 17 20 19 22 21 24 23 25 26 28 27 30 29 32 31 34 33 36 35 38 37 40 39 TO CMAXQUSB R1 500 WPZ R7 470 S1 CSZ ALMZ VCC GND GND C1 0.1F VCC CHIP R2 VCC VBAT CHIP 100 32kHz TP1 TP GND TP1 TP GND 1k RP1 PIO10 PIO6 PIO2 X1 X2 RSTZ WDI WDOZ WPZ PIO0 PIO4 PIO8 1 2 3 4 5 6 7 8 9 10 11 12 13 14 VCC X1 X2 RSTZ WDI WDOZ WPZ PIO0 PIO4 PIO8 GND PIO10 PIO6 PIO2 VCC U1 1 2 3 4 5 6 7 8 SW DIP-8 SB1 VCC CHIP 16 15 14 13 12 11 10 9 VBAT CSZ SCK SI SO ALMZ PIO1 PIO5 PIO9 GND PIO11 PIO7 PIO3 VCC VBAT CHIP PIO7 PIO6 PIO5 PIO4 PIO3 PIO2 PIO1 PIO0 VCC 100k RP2 BATT SRC J3 28 VBAT CHIP 27 CSZ SCK 26 SI 25 24 SO 23 ALMZ PIO1 22 21 PIO5 20 PIO9 19 18 PIO11 17 PIO7 16 PIO3 15 BATTERY VCCLOAD R6 250 2 1 DS28DG02 R5 500 BATTERY B1 PIO8 PIO9 PIO10 PIO11 RESET SW1 RSTZ WDOZ ALMZ J1 1 PIO11 PIO10 PIO9 PIO8 PIO7 PIO6 PIO5 PIO4 PIO3 PIO2 PIO1 PIO0 1 2 3 4 5 6 7 8 9 10 11 12 J6 RSTZ D1 PIO HEADER PIO8 D5 PIO9 D4 PIO10 D3 PIO11 D2 RESET LED ENABLE 2 R3 10k WDOZ D1 R9 10k ALMZ D6 R8 10k VCC 470 RP3 Evaluates: DS28DG02 DS28DG02 Evaluation Board/Evaluation System DS28DG02 Evaluation Board/Evaluation System Evaluates: DS28DG02 Figure 11. DS28DG02 EV Board Layout Top ______________________________________________________________________________________ 17 Evaluates: DS28DG02 DS28DG02 Evaluation Board/Evaluation System Figure 12. DS28DG02 EV Board Layout Bottom 18 ______________________________________________________________________________________ DS28DG02 Evaluation Board/Evaluation System Evaluates: DS28DG02 Figure 13. DS28DG02 EV Board Layout Composite ______________________________________________________________________________________ 19 Evaluates: DS28DG02 DS28DG02 Evaluation Board/Evaluation System Revision History REVISION NUMBER REVISION DATE 0 7/07 Initial release. -- 1 5/08 Removed technical support ticketing system link from the Support Resources section and replaced with the company technical support web address. 1 DESCRIPTION PAGES CHANGED Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 20 ________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.