STM8 Core

[ag123]

among the 'tricks' for using 4.2v lipo i think is to use those cheap diodes with a 0.6-0.7v forward voltage.
https://www.newark.com/pdfs/techarticle ... sBrchr.pdf
https://www.diodes.com/assets/Datasheets/ds28002.pdf
it would take just 2 pieces in series to get 3v from a 4.2v LIPO,or perhaps it may even be possible to make do with just a single diode
alternatively, we could simply connect an LDO or use the existing one on MM/BP

[RogerClark]

Yes.

I use diodes a lot

[zoomx]

This types of cpu's are not C friendly (6 registers and 20 addressing modes..). Best to program it in asm

I programmed only two MCU in asm, ST6 and ST9, some decades ago. ST6 didn't had a flash but a UV erasable memory. They where the first MCU that I used. ST6 was popular in Italy because an italian magazine, Nuova Elettronica, published a course for it with many examples and a beautiful asm skeleton to start.
The magazine had a particular style of schematic drawings that is still used by Pighixxx http://www.pighixxx.com for his schematics.

[RogerClark]

Its been a long long time since I did any assembler.

I think possibly on the Z80 or 6502

[Pito]

ST6 was popular in Italy..

.. and ST started as SGS Microelettronica..
The ST8 architecture is "similar" to the 65xx/68xx and 65/68 are known for lacking a good C. All developments in past were mostly made in asm..

[zoomx]

I don't understand.
Here it is the STM8 CPU programming manual
http://www.st.com/content/ccc/resource/ ... 161709.pdf
at page 10 is written

Code: Select all

The Analog to Digital Converter uses a sample and hold technique. It has 12-bit resolution.

I was very surprised because 12 bit is not common.
But here it is an Application Note Using the analog to digital converter of the STM8S microcontroller
http://www.st.com/content/ccc/resource/ ... 176594.pdf

Code: Select all

STM8 family microcontrollers include one Analog to Digital Converter which has up to 16 
multiplexed inputs. Depending on the STM8 device, the ADC can be one of two types:
●
A basic ADC type named ADC2 
●
An extended ADC type named ADC1 
The resolution of both ADC types is 10 bits. The number of external analog inputs depends 
on the package size of the chosen STM8 family device

I believe that the AN is correct and the manual didn't say that maybe "some" STM8 chips have 12 bit ADC.

[Pito]

Only STM8L and STM8AL chips have got 12bit ADC. See the parameter finder
http://www.st.com/en/microcontrollers/s ... tId=SC1244

[zoomx]

.. and ST started as SGS Microelettronica..

Before was SGS-Ates Componenti elettronici S.p.A. It was here
https://www.google.it/maps/@37.4389452,15.0645871,18z
in the same place of the new bigger factory they do research and production but no MCU. Many years ago they produced components for CFL lamps.
I still have an old ATES transistor somewhere.

Only STM8L and STM8AL chips have got 12bit ADC.

The programming manual don't say that ADC can be 10 or 12 bit, it say only 12. Maybe because it is the programming manual and no one read it.

[Pito]

Last time I read a programming manual carefully was in summer '82 - it was 1 page A4 with all 8080 instructions listed
Even so my first asm code crashed as I was using 8085

[zmemw16]

the 328 supply voltage v frequency graph does allow operation at 3v3 most likely around 8MHz, istr illicit operation at 10MHz being reported.
somewhere i've dozen or so 3v3 nano, mini or similar without usb needing a usb/serial block.
stephen