That is impressive! Seems to be an 8-bit RISC with no registers, just
an accumulator, a cute concept. 1K of program OTP and 64 bytes of ram,
enough for plenty of MCU things. Didn't check if it has an ADC or PWM.
I like that it's in a 6-pin SOT23 package since there aren't many other
MCUs that small.
Reply by ●October 11, 20182018-10-11
On Wed, 10 Oct 2018 19:29:13 -0700, Paul Rubin
The cost of the ICE is not going to be significant for most people - you
usually use a chip like this when you want huge quantities (even though
it is available in small numbers).
What turns me off here is the programming procedure for the OTP devices.
There is no information on it - just a simple one-at-a-time programmer
device. That is useless for production - you need an automated system,
or support from existing automated programmers, or at the very least the
programming information so that you can build your own specialist
programmer. There is no point in buying a microcontroller for $0.03 if
the time taken to manually take a device out a tube, manually program
it, and manually put it back in another tube for the pick-and-place
costs you $1 production time.
Reply by Paul Rubin●October 11, 20182018-10-11
> There is a lot of operations that will update memory locations, so why
> would you need a lot of CPU registers.
Being able to (say) add register to register saves traffic through the
accumulator and therefore instructions.
> 1 KiB = 0.5 KiW is quite a lot, it is about 10-15 pages of commented
> assembly program listing.
It would be nice to have a C compiler, and registers help with that.
> At least the 8 pin version has both a PWM as well as a comparator, so
> making an ADC wouldn't be too hard.
Reply by Philipp Klaus Krause●October 12, 20182018-10-12
Am 12.10.2018 um 01:08 schrieb Paul Rubin:
> firstname.lastname@example.org writes:
>> There is a lot of operations that will update memory locations, so why
>> would you need a lot of CPU registers.
> Being able to (say) add register to register saves traffic through the
> accumulator and therefore instructions.
>> 1 KiB = 0.5 KiW is quite a lot, it is about 10-15 pages of commented
>> assembly program listing.
> It would be nice to have a C compiler, and registers help with that.
Looking at the instruction set, it should be possible to make a backend
for this in SDCC; the architecture looks more C-friendly than the
existing pic14 and pic16 backends. But it surely isn't as nice as stm8
reentrant functions will be inefficent: No registers, and no sp-relative
adressing mode. On would want to reserve a few memory locations as
pseudo-registers to help with that, but that only goes so far.