Preliminary
SN8P1702A/SN8P1703A
8-bit micro-controller build-in 12-bit ADC
PROGRAM CHECK LIST
Item
Description
Use PnUR register to enable or disable on-chip pull-up resisters. Refer I/O port chapter for
detailed information.
Pull-up Resister
Undefined Bits
All bits those are marked as “0” (undefined bits) in system registers should be set “0” to avoid
unpredicted system errors.
ADC
PWM0
Set ADC input pin I/O direction as input mode and disable pull-up resister of ADC input pin
Set PWM0 (P5.4) pin as output mode.
PWM1
Set PWM1 (P5.3) pin as output mode.
Interrupt
Do not enable interrupt before initializing RAM.
Non-used I/O ports should be pull-up or pull-down in input mode, or be set as low in output
mode to save current consumption.
Non-Used I/O
Sleep Mode
Stack Buffer
Enable on-chip pull-up resisters of port 0 and port 1 to avoid unpredicted wakeup.
Be careful of function call and interrupt service routine operation. Don’t let stack buffer
overflow or underflow.
1. Write 0x7F into STKP register to initial stack pointer and disable global interrupt
2. Clear all RAM.
System Initial
3. Initialize all system register even unused registers.
1. Enable OSG and High_Clk / 2 code option together
2. Enable the watchdog option and internal RC for the watchdog clock to protect system
crash.
Noisy Immunity
3. Non-used I/O ports should be set as output low mode or input with pull-up resistors.
4. Constantly refresh important system registers and variables in RAM to avoid system
crash by a high electrical fast transient noise.
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