PFS122
8bit MTP MCU with 12-bit R-Type ADC
Technology is not responsible for this: the quality of the user's crystal oscillator is not good, the usage
conditions are unreasonable, the PCB cleaner leakage current, or the PCB layouts are unreasonable.
9.2.2. Interrupt
(1) When using the interrupt function, the procedure should be:
Step1: Set INTEN register, enable the interrupt control bit
Step2: Clear INTRQ register
Step3: In the main program, using ENGINT to enable CPU interrupt function
Step4: Wait for interrupt. When interrupt occurs, enter to Interrupt Service Routine
Step5: After the Interrupt Service Routine being executed, return to the main program
* Use DISGINT in the main program to disable all interrupts
* When interrupt service routine starts, use PUSHAF instruction to save ALU and FLAG
register. POPAF instruction is to restore ALU and FLAG register before RETI as below:
void Interrupt (void)
{
// Once the interrupt occurs, jump to interrupt service routine
// enter DISGINT status automatically, no more interrupt is
accepted
PUSHAF;
…
POPAF;
}
// RETI will be added automatically. After RETI being executed, ENGINT status
will be restored
(2) INTEN and INTRQ have no initial values. Please set required value before enabling interrupt function.
(3) There are two sets of external IO pin interrupt source. Every set is decided by code option Interrupt Src0
and Interrupt Src1 corresponding to the unique interrupt pin. Please comply with the inten / intrq / integs
register when selecting IO pin.
9.2.3. System clock switching
System clock can be switched by CLKMD register. Please notice that, NEVER switch the system clock and
turn off the original clock source at the same time. For example: When switching from clock A to clock B,
please switch to clock B first; and after that turn off the clock A oscillator through CLKMD.
Example : Switch system clock from ILRC to IHRC/2
CLKMD
=
0x36;
0;
// switch to IHRC, ILRC can not be disabled here
// ILRC can be disabled at this time
CLKMD.2 =
ERROR: Switch ILRC to IHRC and turn off ILRC simultaneously
CLKMD 0x50; // MCU will hang
=
9.2.4. Watchdog
Watchdog will be inactive once ILRC is disabled.
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PDK-DS-PFS122-EN_V000-May 28, 2020
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