© Freescale Semiconductor, Inc., 2005. All rights reserved.
Freescale Semiconductor
User Guide
DEMO9S08QG8_APP
Rev. 0.02, 09/2005
DEMO9S08QG8_APP Example
Application User Guide
Introduction
This document describes how to set up and use the DEMO9S08QG8_APP example application that comes
with the DEMO9S08QG8 demo board. This example application allows the user to try out several features on
Freescale’s MC9S08QG8 microcontroller.
Requirements
To run this software, you will need the following:
• DEMO9S08QG8 demo board with an MC9S08QG8 in the 16 DIP socket
• DB9 serial cable
•PC with:
– CodeWarrior Development Studio for HC(S)08
– CodeWarrior Service Pack for MC9S08QG8 (download from www.metrowerks.com)
– Terminal emulation program, e.g., HyperTerminal
Setting up the Demo
1. Connect the DEMO9S08QG8 to the PC as described in the Quick Start Guide. The jumper
configuration for this application is:
– COM_EN jumper removed
– SW1, SW2, LED1, RV1, RZ1 jumpers installed
– LED2 jumper optional
2. Connect the DB9 serial cable and the USB cable between the DEMO9S08QG8 and the PC.
3. Open CodeWarrior IDE and open the DEMO9S08QG8_APP project.
4. Compile for the P&E ICD target and program the MCU by selecting “P&E ICD” from the pull-down menu
beneath the project name. Then click the debugger icon, as shown in Figure 1). This will launch the
debugger application and ask, “Erase and program FLASH”. Click on “Yes”. When the programmer
pop-up window goes away, the MCU is programmed.
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Running the Demo
Figure 1. CodeWarrior Project Window (Step 4)
After the MCU is programmed, launch the terminal emulator. The emulator must be configured to use the COM
port that the DB-9 cable is plugged into, usually COM1. The COM port settings must be:
• 4800 baud
• 8 bits
• No parity
•1 stop bit
The demo is now ready to run.
Running the Demo
If necessary, open the True-Time Simulator. Select Run -> Start/Continue(F5) to launch the application.
If everything is configured correctly, the terminal window will display the following as soon as the MCU is
running:
Welcome to the MC9S08QG8 Demo Application
V1.0
Main Test Menu:
1: ICS setup
2: TPM PWM setup
3: MTIM setup
4: RTI setup
5: STOP test
6: ACMP test
7: ADC test
Select number to execute:
This demo relies on the internal clock reference to generate bus frequency and the communications baud rate.
Therefore, the MCU’s internal clock reference must be trimmed to 31.25 kHz and the trim value stored in
First, Select “P&E ICD”
2. Then, Click Debugger Icon
Demo Menu Options
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FLASH at location 0xFFAF. CodeWarrior with the MC9S08QG8 Service Pack will trim and save the trim value
automatically.
The 31.25 kHz reference will generate an 8.0 MHz bus clock in FEI mode. The demo will light LED1, and the
MCU’s TPMCH1 pin will be outputting a PWM signal running at 1/10,000 of the bus frequency. If the internal
reference is trimmed, this PWM signal should be 800 Hz ±2%.
RESET Button and SRS Register
After every chip reset, the display will show the value of the System Reset Status (SRS) register and state the
cause or causes of the last reset.
For this demo application, the RESET pin on the MC9S08QG8 is configured as a general purpose PTA5 input,
not as RESET. However, the program uses PTA5 to determine whether the COP should be serviced. If the
RESET button (connected to the PTA5/IRQ/TCLK/RESET pin) is not pressed, the COP will be serviced and
no COP reset will be generated. If the RESET button is pressed, the COP will not be serviced and will therefore
timeout, forcing a chip reset.
Because the cause of the reset is actually the COP and not the RESET pin function, the SRS will indicate a
COP reset occurred instead of a pin reset.
Demo Menu Options
The user can choose from eight options to explore a handful of the MC9S08QG8’s features. The options allow
the user to choose from several ICS setups, change the TPM clock source, reconfigure the MTIM settings,
measure the RTI’s internal reference, and try out the different stop modes, the ACMP, and the ADC modules.
To make a selection, simply type the number next to the menu item. Some menu choices will require a two-
digit value. For these items, type the two-digit number followed by <Enter>. When entering these two-digit
values, the delete and backspace keys will not work. To re-type a value, enter a non-hexadecimal value and
the menu will ask for a new entry.
ICS setup
This option allows the user to select from five different settings of the Internal Clock Source (ICS) module. Four
of the settings are using FEI mode (FLL-enabled, internal clock reference) with different bus divider values and
one option selects FBI mode (FLL-bypassed, internal clock reference).
TPM PWM setup
This option simply lets the user change the clock source to the TPM (Timer/PWM Module). One of the choices,
“TCLK source”, requires a clock signal to be input on the PTA5/IRQ/TCLK/RESET pin. If no clock source is
present, the timer will not count and the PWM signal will freeze. The demo will continue to run.
MTIM setup
This menu option allows the user to do several things with the MTIM (Modulo Timer Module): initiate a software
PWM signal running at 1/100 of the bus frequency, choose a different clock source, set the clock source
prescaler, set the timer modulo value, start, stop and reset the MTIM.
As with the “TPM PWM setup”, if the TCLK is selected as the MTIM clock source, a clock signal must be input
on the PTA5/IRQ/TCLK/RESET pin. If no clock source is present, the MTIM will not count and the software
PWM signal will freeze. The demo will continue to run.
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Demo Menu Options
RTI setup
This menu item has several choices for using the RTI (Real-Time Interrupt) feature. All three choices configure
the RTI to use its internal 1-kHz clock source. This clock source is independent of the ICS’s internal clock
reference and cannot be trimmed like the internal clock reference can.
The three choices are: measure the RTI timeout period, start the RTI, and stop the RTI.
Measuring the RTI configures the RTI for a 1 second timeout period and runs the TPM and MTIM while waiting
for the RTI flag to timeout. The TPM and MTIM counter values are displayed along with the expected value if
the RTI’s clock source was exactly 1 kHz. Values less than expected mean the RTI clock is fast; values greater
than expected mean the RTI clock is slow.
The “RTI on” option will not appear to do anything on the screen. However, if the RTI is turned on and then the
“STOP tests” menu is used to enter stop 2 or stop3, the RTI will automatically wake the MCU out of the stop
mode. The “RTI off” can be used if the user wishes to remain in the stop modes.
STOP test
The “STOP test” options allow the user to configure the MCU for either stop1, stop2, or stop3 mode and then
enter stop mode. As mentioned in the “RTI setup”, if the RTI is on and the MCU enters stop2 or stop3 (the RTI
does not run in stop1 mode), then the RTI will wake the MCU from stop when it times out.
NOTE
After stop1 or stop2 has been selected, the selected stop mode cannot be
changed until the MCU has been powered off and back on.
NOTE
If stop1 or stop2 is selected, the internal pullup on the
PTA5/IRQ/TCLK/RESET pin is disabled. Therefore, an external pullup is
required on this pin or the MCU may not stay in stop mode.
ACMP test
When enabled, the ACMP (Analog Comparator) test configures the ACMP to compare the voltage on the
photosensor (RZ1) to the potentiometer (RV1). The output of the ACMP is configured by software to be the
trigger for the TPMCH0 input capture. The demo measures the time between each toggle of the ACMP output.
Adjusting RV1 will change the amount of darkness necessary to toggle the ACMP.
ADC test
The “ADC test” has two options: measure the voltages on the photosensor (RZ1) and the potentiometer (RV1)
or measure the bandgap voltage. The reading of the bandgap voltage will not change (except for very small
changes due to board noise) unless the VDD of the MCU is changed.
