1. Software compatibility ?
2. Development tool compatibility ?
3. Any other important points in regards to replacement ?
- Software Compatibility
The instruction systems are identical. However, the 7542/7546/7547 Group contains two additional multiplication (MUL) and division (DIV) instructions. Since, compared to the 7531 Group, the 7542/7546/7547 Group has more functions (or partial functional changes), the programs for the 7531 Group cannot be operated in the 7542/7546/7547 Group without modification.
- Compatibility of Development Tools
If the emulator MCU is changed to the M37542RSS, programs for the 7542/7546/7547 Group can be developed using the development tool used in the 7531 Group.
- Notes on Replacement
The number of interrupt factors and interrupt vectors are both increased for functional additions. Some of the interrupt factors are common to both Groups but with different vector address, thus some changes are required. Also, the on-chip oscillator can be used as an operation clock in the 7542/7546/7547 Group, achieving low-power operation.
For information on replacing MCUs, the following documents are available in "Application Notes". -> here
The document on differences between the 7544 Group and 7531 Group are also available. -> here