User guide

16-bit MCU: S12XHY256 Automotive Cluster Demo, Rev. 0
Preliminary—Subject to Change Without Notice
FAQs and Talking Points
Freescale Semiconductor4
— LEFT TURN, switch 9, controls TEMP indicator light. Pressing the LEFT TURN switch for a
few second (after the horn sound has passed), will turn off TEMP indicator for 10s.
— RIGHT TURN, switch 8, controls RPM indicator light. Pressing the RIGHT TURN switch for
a second will turn off RPM indicator for 10s.
• This demo is capable of identifying RTZ (return-to-zero) position either by SSD (Stepper Stall
Detection) hardware module or by SSD software logic at demo power up. This is configured at
project compilation time, the current SSD implementation is displayed while the four stepper
motors are calibrating the zero position at power up:
— SSd-h- for SSD HW RTZ implementation.
— SSd-S- for SSD SW RTZ implementation.
For this S12XHY demo you will see SSd-h- message.
NOTE
SSD is only active during startup at RTZ calibration. After RTZ position has
been determined the motors deactivate this logic and start moving CW and
CCW.
The odometer value displayed on the LCD is also of importance. The user will notice that on switching on
or switching off the demo, the odometer value is maintained despite the S12XHY device having no
EEPROM. The demo uses an emulated EEPROM software driver, available freely on the Freescale
website, which uses the device’s D-flash to read and write the odometer values.
3 FAQs and Talking Points
1. Is the SSD software available for general use?
— An application note, AN4024 has been released explaining the SSD software technique and is
available with demo software.
2. Only the odometer value is restored upon POR, why isn’t the other values restored?
— This is for demonstration purposes and as such only the odometer value has been programmed
with the EEE driver. Other values such as the trip A/B meter can be implemented in the same
way.
3. How is the shaft pointers illuminated?
— The motors include an integrated white LED, which is connected directly to a GPIO. It should
be pointed out that these require a GPIO each. So, controlling the GPIO in a general manner
for initiating LEDs is how it’s done.
4. The demo board contains a CAN and LIN Molex connector, do these work?
— Yes, they work; but have not been enabled on this demo.
5. Where can I find the schematics of the demoboard? Is the demo code available?
— When you purchase the board, Axiom provides a CD with both schematics and software. The
firmware for this demo is not openly available.
6. I don’t like the piezoelectric speaker sound, can I change it?