Question about renesas R32C/11

Question

Hi guys, 
 
 I new user with family R32C/111. I have read R32C it is 32-bit CICS, but when I download and read it's datasheet, I have found out that it has only CPU 32bit registers but peripherals has only 8-bit control registers (SPI, UART, ADC..). For me it's weird because I worked with ARM 7, CORTEX-M0, 3,4.They are 32-bit MCU, so they have 32-bit core register and thus have 32-bit control register peripherals. Then Microchip PIC18 - 80bit MCU, that's 8-bit core and 8-bit peripherals , PIC32 that's 32-bit core and 32-bit peripherals 
 My questions are: 
 What's new here? and why CISC 32-bit family RENESAS has this architecture? 
 
 Thank you.

FrankL · Accepted Answer

The classification of a CPU is ONLY done on the saize of the CPU registers. §2-bit registers, 32-bit processor. 
 The peripheral registers have nothing to do with this. 
 ARM usually access data 32-bit aligned as this is the fastest access. So they use this also for peripheral registers. The registers themselves are often smaller. 
 For R32C there is no speed advantage if a data is not aligned or if it is aligned to 16 or 32 bit as long as the data can be read in one cycle. This makes the memory map of R32C smaller than that of a comparable ARM processor. This is not so important for peripheral regsiters but may have an advantage for RAM variables as for variables the same alignment rules apply. 
 When looking at Renesas processors it is the better choice to use RX instead of R32C.