The ST7 family is in obsolescence so it is necessary to completely redo the SW and the HW to switch to:
- STM8S – 5V High performance 8bit with EEPROM
- STM32 – 32bit is a classic 3.3V but is 5V tolerance, some STM32 integrated also EEPROM – STM32G0 family is recommended, it has only two power pins, it is particularly robust against disturbances because it integrates the ground and power planes,
Here are some of our thoughts on why, having to make the leap, it’s best to use a Cortex Mx (STM32).
There is this AN (AN2945) that highlights the advantages of STM8S and STM32.