PSoC™ 4 HVPA: Recommend using IMO = 48 MHz even for 24 MHz device – KBA237886
If the customer application has the flash programming operation, the IMO is recommended to be set to 48 MHz (49.152 MHz), even for the part numbers that only support 24 MHz system operation.
To program flash, PUMP clock is required. It is used to drive the charge pumps of the flash and for program/erase timing purposes. This clock must be set to 48 MHz ± 4 MHz.
For part numbers that only support the 24 MHz system operation, it is recommended to set IMO to 48 MHz and source the PUMP clock directly with IMO while configuring the system clock (SYSCLK) to a slower frequency with divider and prescaler to run the CPU.
For the part numbers that only support the 24 MHz system operation, configure the IMO to 24 MHz for other functions of the customer application, and change the IMO and the pump clock to 48 MHz only when programming flash. Because all other functions need to be stopped to re-configure the whole clock system every time when changing IMO frequency, the PACSS measurements performance will be seriously impacted.
In conclusion, it is recommended to use the IMO = 48 MHz setting, even for the part numbers that only support 24 MHz system operation.
For details, please refer to chapter 10.2.1 of PSoC™ 4 HVPA Architecture TRM.
Note: This KBA applies to the PSoC™ 4 HV family MCUs.
- PSoC™ 4 HVPA series