STM32H503 - Timing feasibility using an external RTC
Hi...
Greetings...
We're planning to use STM32H503 MCU in our application.
To brief about our application, we've a parallel RTC IC which has gone EOL. This RTC receives commands from the motherboard MCU. So, we're mimicking the RTC's functionality using a microcontroller and a serial RTC in a castellation PCB (smallest form factor). With the microcontroller's GPIO, we're trying to achieve parallel interface. Attached the timing diagram in this thread. Since it's a time critical application, we are preferring to go with a high speed MCU.
The flow of timing diagram goes like this...
When CS0 becomes low, the address is present in the address bus (4 bit). When CS0 goes low, within min. 50ns, Read / Write pin goes low.
During read operation, the data corresponding to the address needs to be placed in data bus (4 bits of data) within 120ns max. During write operation, the data needs to be read from the data bus within 90ns.
Considering the crucial timing, we are checking the feasibility to use STM32H503 MCU (32 pin variant)
Kindly let us know the minimum instruction time of that MCU when it's clocked at Max. 250MHz (internal clock source). As the PCB dimensions are too small, we're expecting the smallest package for the MCU.
Kindly provide your comments on whether our timing requirements before met by STM32H503 MCU. Also kindly confirm if the 32 pin variant in that series support internal RTC.
Best Regards,
Prahaladh S
