...i was "lectured" by another person on this forum some time ago that,
8 bit is faster for bitbanging
And apparently the STM8L is the king of the 8bit market
Why is 8-bit faster for bitbanging?
The bit size of a proccesor only means how big registers in the proccesor are. A 32-bit processor can easily work with bytes.
For e.g. I have done SPI bitbanging on a PIC32 running at 80MHz. I was only able to analyze the signal (like SCK) if I put extra delays in the code (NULL commands) , otherwise the 50MHz tek scope @ college couldn't pick it up..
I do give you though, that most ARM processors don't allow for quick I/O toggling because of their architecture. The new GPIO values have to propogate through all the AHB busses , matrices, switches etc. etc. , and will add considerable delays.
Some MCU's support Fast GPIO where it's directly on the CPU bus. But typically fairly limited. However, if bit banging is too slow then try to use a peripheral (adapt SPI, I2C, camera, memory busses etc), it's much faster and you get DMA (if you need high throughput).
Anyway, if you want to ditch IAR (which I probably am going to do), CooCox sounds like a great alternative:http://www.coocox.org/CooCox_CoIDE.htm
It's free to use.
They support Cortex M4 and the STM32F4 too.
I'm uncertain if the STM8 is a 'king' at all. Like I never actually looked into ST MCU's untill I saw the STM32F4 with a 7MSPS ADC (which I plan to use for a future project).
Their 8-bit MCU's seem alright, but I don't see any advantage or disadvantage to using a modern PIC or an AVR.
Well I guess having DMA and a 1MSPS ADC + DAC on such a low entry MCU is nice. Problem is, if the project doesn't need it, you still don't gain any advantage
In general, I'd rather ditch 8-bit completely and pick something 16-bit or even 32-bit all the time. Look at NXP Cortex m0 series, they are fast , lots of space and peripherals, one set of tools (Cortex m0 to m4), small (I believe there are some TSSOP and even DIP versions) and cheap (few dollars).