Author Topic: STC 8051 MCUs: yay or nay?  (Read 10603 times)

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Offline technix

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STC 8051 MCUs: yay or nay?
« on: October 22, 2016, 06:14:09 pm »
A lot of folks here (in China) are suggesting me to take a look at STC 8051 MCUs. What is your opinions on those chips?

I grabbed a starter kit for those chips (either 2 chips or the minimum order amount, so I can have a backup chip to play with if I let the smoke out of one of them) But because those chips are so cheap my starter kit included 6x IAP15F2K61S2 (supports OCD, 2x DIP-40, 2x DIP28, 2x low-voltage DIP-40,) 2x IAP15W4K61S4 (supports OCD, DIP-40,) 10x IAP15W413AS (5x DIP-20, 5x DIP-16) and 5x IAP15W105 (DIP-8)

So far to me...
* Their chips are cheap. Almost ridiculously cheap. The cheapest chip STC15W100 (512 bytes Flash ROM, 128 bytes RAM, no EEPROM, next to no peripheral, SO-8 package) costs 15 US cents. While the most expensive IAP15W4K61S4 (61kB unified Flash ROM, 4kB RAM, OCD, tons of goodies built in, DIP-40 package) still cost less than a dollar.
* They are locally produced in TSMC fab in Shanghai.
* They do not follow the traditional 8051 pinout.
* Selectable quasi-bidirectional, push-pull, or open-drain/high impedence pin modes.
* Not all models comes with on-chip debug, but for the ones that have OCD (often highest-end IAP models in their respective lines, like IAP15F2K61S2 or IAP15W4K61S4) the debug feature uses normal UART0 pins (while UART0 itself can be multiplexed onto other pins so still useable.) OCD is only available if you are using Keil uVision IDE.
* Normal UART0 pins are also used for ICSP using some kind of UART-based protocol, even for those chips that does not have built-in UART.
* Models start with STC implements strict Harvard architecture, usually with some built-in data Flash ROM in its own memory space. Strangely MOVC instruction can also be used to read from data Flash, by adding an offset to the address.
* Models start with IAP implements a modified Harvard architecture with unified program/data Flash ROM instead of dedicated data Flash ROM, with the same address in data Flash ROM space mapping to the same address in program memory space, and RW access using the same EEPROM registers.
* Lots of on-chip goodies especially on those bigger chips like IAP15W4K61S4 or IAP15F2K61S2. Some peripherals are even located in XRAM.

Their model names for STC15 series are fairly simple to decode though.

* model-name = prefix + "15" + voltage + RAM + program Flash + additional features + "-" + package
* prefix = "STC" for normal chips, "IAP" for ones with unified program/data Flash ROM, "IRC" for ones with unified Flash and cannot use external reset
* voltage = "F" for 5V, "L" for 3.3V, "W" for wide 2.7-5.5V operation.
* RAM = "1" = 128B, "2" = 256B, "4" = 512B, "1K" = 1kB, "2K" = 2kB, "4K" = 4kB
* program flash = program Flash (for STC15) or unified Flash (for IAP/IRC15) space in kB

I am exploring those chips using their flagship chip and writing up my experiences. You can read it if you are interested: https://en.maxchan.info/tag/stc
« Last Edit: October 22, 2016, 08:51:49 pm by technix »
 

Online mikeselectricstuff

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Re: STC 8051 MCUs: yay or nay?
« Reply #1 on: October 22, 2016, 06:36:31 pm »
"cheapest MCU" is a frequent topic here - I'm sure plenty of people would be interested to see your experiences with them
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Online mikeselectricstuff

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Re: STC 8051 MCUs: yay or nay?
« Reply #2 on: October 22, 2016, 06:38:17 pm »
Interesting snippets from their datasheet :
Quote
the  eighth  generation  of  STC  encryption  technology ,  there  is a  reward  of  100  thousands  yuan RMB  for the gaps in encryption now.

Quote
China's  home-grown  independent  intellectual  property  rights,  Please  all  Chinese  people  support  us,
your surport is a powerful guarantee of China' home-grown business development.

..well apart from that 8051 core...
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Offline technix

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Re: STC 8051 MCUs: yay or nay?
« Reply #3 on: October 22, 2016, 07:02:22 pm »
Interesting snippets from their datasheet :
Quote
the  eighth  generation  of  STC  encryption  technology ,  there  is a  reward  of  100  thousands  yuan RMB  for the gaps in encryption now.

Quote
China's  home-grown  independent  intellectual  property  rights,  Please  all  Chinese  people  support  us,
your surport is a powerful guarantee of China' home-grown business development.

..well apart from that 8051 core...
From what I have heard that they designed their own core, only kept the 8051 ISA intact as it is really old and not patent encumbered.
 

Offline danadak

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Re: STC 8051 MCUs: yay or nay?
« Reply #4 on: October 22, 2016, 08:40:44 pm »
If its dirtball low end penny stuff there are a number of vendors that
can meet that.

Cypress has an 8051 core in their PSOC stuff, capabilities look like -

For me what stands out is -

1) Routability
2) Fast 12 bit SAR A/D and slow 20 bit DelSig
3) DFB (Digital Filter Block) that is dual channel, handle FIR or IIR filters, or DFB
can be used as a GP fast processor block, sililiar to RISC block
4) MSI logic elements GUI based and/or the UDB Verilog capability. Eg. the FPGA
like capability
5) Onboard Vref
6) DAC, IDAC, OpAmps (up to 4), comparator, mixer, switch cap, analog mux....
7) LCD
  COM, UART, I2C, I2S, One Wire, SPI, Parallel, LIN, CAN, BLE
9) Custom components capability
10) DMA to offload processes like filters
11) ARM M0 or M3 or 8051 core
12) Extensive clock generation capabilities

https://www.element14.com/community/thread/23736/l/100-projects-in-100-days?displayFullThread=true

http://www.cypress.com/documentation/code-examples/psoc-345-code-examples

Great video library

Attached component list. A component is a HW onchip resource.

Free GUI design tool with schematic capture, "Creator". Components have rich API library attached
to each component

This is low end of family, consider 5LP parts as well. PSOC also has arduino footprint boards (pioneer) as well

https://www.elektormagazine.com/labs/robot-build-with-cypress-psoc

http://www.cypress.com/products/32-bit-arm-cortex-m-psoc


But these are not 25 cent chips. They do have ARM M0 based PSOC parts that get << $ 1 though.


Regards, Dana.
« Last Edit: October 22, 2016, 08:46:57 pm by danadak »
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Offline westfw

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Re: STC 8051 MCUs: yay or nay?
« Reply #5 on: October 22, 2016, 11:05:17 pm »
Quote
STC 8051 MCU
12 cycle core or something newer?
 

Online mikeselectricstuff

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Re: STC 8051 MCUs: yay or nay?
« Reply #6 on: October 23, 2016, 12:04:51 am »
Datasheet says 1 clock per machine cycle
http://www.stcmcu.com/datasheet/stc/STC-AD-PDF/STC15-English.pdf

first time I've seen prices in a datasheet..!
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Offline janekm

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Re: STC 8051 MCUs: yay or nay?
« Reply #7 on: October 23, 2016, 03:57:43 am »
ST are competing heavily against STC in the Chinese market (are the names a coincidence?  >:D) by practically price-dumping on the STM8 range of chips.
STM8S003F3P6 gets advertised at under 1RMB, volume pricing might be slightly lower still.

And that's a much more modern, "sensible" design than the STC51 as far as I can see, with all the modern peripherals you'd expect, even 10bit ADC, of course on chip debugging, UART, I2C, SPI, ...

The cheapest model has 1KB of RAM and 8KB of Flash.

BTW I see the STM8 line much more commonly used on really low-cost Chinese products (like 10RMB LED controllers etc) than the STC line.
 

Offline technix

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Re: STC 8051 MCUs: yay or nay?
« Reply #8 on: October 23, 2016, 04:19:57 am »
ST are competing heavily against STC in the Chinese market (are the names a coincidence?  >:D) by practically price-dumping on the STM8 range of chips.

I would say for a new generation designer, moving to STM8 or MSP430 is sensible, but for old engineers who have been working on 8051 for their entire career, or companies want to reuse IP from AT89C51, STC would be a better choice.
Also, for universities, using domestic parts will attract more funding from government fed funding sources.
Agreed. At least in my school courses involving microcontrollers are designed around STC chips.
 

Online nctnico

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Re: STC 8051 MCUs: yay or nay?
« Reply #9 on: October 23, 2016, 10:24:14 am »
IMHO using a low cost 8051 base MCU makes only sense in very high volume chips nowadays. If you count in the extra engineering time to get around the 8051 limitations the suddenly they aren't so cheap. Going for cheap parts often leads to needing a lot of (unforeseen) engineering time.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline janekm

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Re: STC 8051 MCUs: yay or nay?
« Reply #10 on: October 23, 2016, 10:34:43 am »
Sure, the needs of universities are very different than the needs of industry. It's all about what's convenient for the professors (who are probably more familiar with 8051 in the first place). And I see a lot of dev kits around STC51 which sure look like they're intended for universities or similar educational environments: https://detail.tmall.com/item.htm?spm=a230r.1.14.203.iOyNpp&id=36522460231&ns=1&abbucket=13

But for industry it's a whole other story. I just had a quick look around my desk and here's a few PCBs coming out of different low-cost electronic items designed by Chinese companies.

There's the LED controller PCB, a Qi wireless charger (I have a different model that also uses STM8), a dev board (ok that's cheating), a simple transparent serial over radio module, and a formaldehyde sensor (using STM32, a little over-kill there). That LED controller costs 15.5RMB including enclosure and remote control (the package markings are lasered off but the pinout matches STM8S003 including the internal LDO bypass cap). The radio module is 7RMB.

I haven't yet seen an STC51 in a shipping product (though it's possible that some rub off the package markings, I suppose).
So if you want to learn what's actually used in industry, I'd suggest STM8 or STM32. I've never seen MSP430 used in a Chinese product either.
 

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Re: STC 8051 MCUs: yay or nay?
« Reply #11 on: October 23, 2016, 11:00:37 am »
I don't like either their products, their website, or their boss.  :--

Online nctnico

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Re: STC 8051 MCUs: yay or nay?
« Reply #12 on: October 23, 2016, 11:17:44 am »
I haven't yet seen an STC51 in a shipping product (though it's possible that some rub off the package markings, I suppose).
So if you want to learn what's actually used in industry, I'd suggest STM8 or STM32. I've never seen MSP430 used in a Chinese product either.
IMHO that is not a good starting point for selecting something. You need to select something which fits your application, abilities/skills and budget. Oh, and I have seen an MSP430 in a Chinese product.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline janekm

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Re: STC 8051 MCUs: yay or nay?
« Reply #13 on: October 23, 2016, 11:40:20 am »
I haven't yet seen an STC51 in a shipping product (though it's possible that some rub off the package markings, I suppose).
So if you want to learn what's actually used in industry, I'd suggest STM8 or STM32. I've never seen MSP430 used in a Chinese product either.
IMHO that is not a good starting point for selecting something. You need to select something which fits your application, abilities/skills and budget. Oh, and I have seen an MSP430 in a Chinese product.

Well I stand corrected on the MSP430 then :) I don't like to recommend them as I had some bad experiences around low power modes and part availability but that's a topic for another day, perhaps. They're pretty dead for new designs anyway since even TI is putting ARM cores into their new designs.

Sure, for choosing a part for a new design the criteria are different. But if you have a really low budget and need a jelly-bean micro STM8 is worth looking at.

For learning purposes of course ARM is the obvious choice. And STM32 and NRF51 are also crazy cheap (but still at least 3x the cost of STM8).
 

Offline coppice

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Re: STC 8051 MCUs: yay or nay?
« Reply #14 on: October 23, 2016, 12:16:48 pm »
I haven't yet seen an STC51 in a shipping product (though it's possible that some rub off the package markings, I suppose).
So if you want to learn what's actually used in industry, I'd suggest STM8 or STM32. I've never seen MSP430 used in a Chinese product either.
IMHO that is not a good starting point for selecting something. You need to select something which fits your application, abilities/skills and budget. Oh, and I have seen an MSP430 in a Chinese product.

Well I stand corrected on the MSP430 then :) I don't like to recommend them as I had some bad experiences around low power modes and part availability but that's a topic for another day, perhaps. They're pretty dead for new designs anyway since even TI is putting ARM cores into their new designs.
TI is still very much developing new MSP430 parts, especially FRAM parts. Some are specifically targeted at the China market, which has always been a pretty good market for the MSP430.
 

Offline technix

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Re: STC 8051 MCUs: yay or nay?
« Reply #15 on: October 23, 2016, 02:51:38 pm »
Sure, the needs of universities are very different than the needs of industry. It's all about what's convenient for the professors (who are probably more familiar with 8051 in the first place). And I see a lot of dev kits around STC51 which sure look like they're intended for universities or similar educational environments: https://detail.tmall.com/item.htm?spm=a230r.1.14.203.iOyNpp&id=36522460231&ns=1&abbucket=13

But for industry it's a whole other story. I just had a quick look around my desk and here's a few PCBs coming out of different low-cost electronic items designed by Chinese companies.

There's the LED controller PCB, a Qi wireless charger (I have a different model that also uses STM8), a dev board (ok that's cheating), a simple transparent serial over radio module, and a formaldehyde sensor (using STM32, a little over-kill there). That LED controller costs 15.5RMB including enclosure and remote control (the package markings are lasered off but the pinout matches STM8S003 including the internal LDO bypass cap). The radio module is 7RMB.

I haven't yet seen an STC51 in a shipping product (though it's possible that some rub off the package markings, I suppose).
So if you want to learn what's actually used in industry, I'd suggest STM8 or STM32. I've never seen MSP430 used in a Chinese product either.
When you buy STC chips in bulk you can get whatever you like be lasered on it. And if the amount is large enough you can even get custom pinouts (e.g. IAP15F2K61S2-35I-SKDIP28 in ATmega328P-20PU compatible pinout, IAP15W4K61S4-30I-PDIP40 in AT89C51RC-24PU compatible pinout, or even IAP15L2K61S2-35I-LQFP48 in STM32F103CBT6-compatible pinout.)
 

Offline technix

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Re: STC 8051 MCUs: yay or nay?
« Reply #16 on: October 23, 2016, 02:58:19 pm »
Quote
STC 8051 MCU
12 cycle core or something newer?
They have the 6-cycle STC89/90 series (which comes with an selectable built-in 2x prescaler to emulate 12-cycle timing) and their custom core in STC11/12/15 series that have variable cycle count (1-cycle best case, 6 cycle worst case for hardware division) for each instruction. I am talking about the newer STC15 line here.
 

Offline technix

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Re: STC 8051 MCUs: yay or nay?
« Reply #17 on: October 24, 2016, 07:26:19 am »
I haven't yet seen an STC51 in a shipping product (though it's possible that some rub off the package markings, I suppose).
So if you want to learn what's actually used in industry, I'd suggest STM8 or STM32. I've never seen MSP430 used in a Chinese product either.
IMHO that is not a good starting point for selecting something. You need to select something which fits your application, abilities/skills and budget. Oh, and I have seen an MSP430 in a Chinese product.

Well I stand corrected on the MSP430 then :) I don't like to recommend them as I had some bad experiences around low power modes and part availability but that's a topic for another day, perhaps. They're pretty dead for new designs anyway since even TI is putting ARM cores into their new designs.
TI is still very much developing new MSP430 parts, especially FRAM parts. Some are specifically targeted at the China market, which has always been a pretty good market for the MSP430.
In my school MSP430G2 LaunchPads are handed out like candy to frequent visitors of the professor's lab. I got one with MSP430G2553 on it after my 6th visit of the week, even though I am not a member of his team.

The post-grads there tells me that I should explore outside AVR (myentire microcontroller experience back then was only AVR) so they gave me this as a kickstarter for something other than that. I took that suggestion in heart and started looking around for different architectures for my projects, and start writing application code that works across all platforms. Although I have already set up shop for AVR, PIC and ARM (STM32) platforms, the MSP430 LaunchPad somehow never really worked...
 

Offline technix

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Re: STC 8051 MCUs: yay or nay?
« Reply #18 on: October 24, 2016, 07:50:02 am »
In my school MSP430G2 LaunchPads are handed out like candy to frequent visitors of the professor's lab. I got one with MSP430G2553 on it after my 6th visit of the week, even though I am not a member of his team.

The post-grads there tells me that I should explore outside AVR (myentire microcontroller experience back then was only AVR) so they gave me this as a kickstarter for something other than that. I took that suggestion in heart and started looking around for different architectures for my projects, and start writing application code that works across all platforms. Although I have already set up shop for AVR, PIC and ARM (STM32) platforms, the MSP430 LaunchPad somehow never really worked...

When I was in college, we were taught MSP430, and we had these G2553 boards given to everyone like candy. My senior design project has part of it (1 of totally 3 programmable devices, the others are Intel Galileo and Intel Atom) built with G2553 on my custom PCB.
I've never used IAR out of classroom. I always use MSPGCC for all my projects.

I never got it to actually work. MSPGCC+CCS fares better than IAR - IAR refuses to work outright but CCS at least can build and single step the built-in example code. My senior project had an ATmega328P on it, with code written using Arduino IDE and have the Optiboot bootloader.

I always used code like this as a sanity check of a platform, as it is easy to understand yet it is non-trivial:

Code: [Select]
#include "system.h"

int main(void)
{
  systick_init();
  DDRB |= _BV(4);

  for (;;)
  {
    PORTB ^= _BV(4);
    delay(500);
  }
}

and the Arduino-style timing functions being implemented using timer interrupts. I have working code for AVR (any system clock frequency, using timer 0,) PIC (any system clock frequency, using timer 1,) ARM Cortex-M3 (any system clock frequency, using SysTick timer) and semi-working code for 8051 (any system clock frequency, using timer 0, passed under AT89C51RC@24MHz but failed under IAP15W4K61S4@30MHz.) I have yet to got it to work under MSP430, and how do I make MSP430G2553 run off external 16MHz or 24MHz crystal?
 

Offline coppice

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Re: STC 8051 MCUs: yay or nay?
« Reply #19 on: October 24, 2016, 08:23:19 am »
I never got it to actually work. MSPGCC+CCS fares better than IAR - IAR refuses to work outright but CCS at least can build and single step the built-in example code. My senior project had an ATmega328P on it, with code written using Arduino IDE and have the Optiboot bootloader.
A MSP430 launchpad connected to a PC running IAR is about the easiest development platform to get running in the entire industry. If you could get MSPGCC and CCS to work I assume your hardware was not faulty. Were you using one of the cracked copies of IAR which make the rounds in China? Some of those give trouble with some MSP430 devices.
I have yet to got it to work under MSP430, and how do I make MSP430G2553 run off external 16MHz or 24MHz crystal?
You can't get an MSP430G2553 to run at 24MHz. They only function up to 16MHz. If I remember correctly that device doesn't have the optional fast crystal oscillator. It only has a 32kHz crystal oscillator. You get fast clock rates from the internal DCO. Using a fast crystal generally defeats most of the ultra low power qualities of the MSP430, so few users actually want such an oscillator.
 

Offline coppice

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Re: STC 8051 MCUs: yay or nay?
« Reply #20 on: October 24, 2016, 08:45:15 am »
A MSP430 launchpad connected to a PC running IAR is about the easiest development platform to get running in the entire industry. If you could get MSPGCC and CCS to work I assume your hardware was not faulty. Were you using one of the cracked copies of IAR which make the rounds in China? Some of those give trouble with some MSP430 devices.

I use MSPGCC+MSYS+TI downloader, and the combination works well. Granted, IAR makes debugging HW issues easier, but using GCC and an o'scope plus virtual COM it is still possible to debug HW issues.
The original MSPGCC worked very well. The current MSPGCC, based on a new port TI paid RedHat to produce, still produces poorer code than the old MSPGCC. This is really sad, as GCC is capable of so much better.
 

Offline technix

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Re: STC 8051 MCUs: yay or nay?
« Reply #21 on: October 24, 2016, 08:56:50 am »
I never got it to actually work. MSPGCC+CCS fares better than IAR - IAR refuses to work outright but CCS at least can build and single step the built-in example code. My senior project had an ATmega328P on it, with code written using Arduino IDE and have the Optiboot bootloader.
A MSP430 launchpad connected to a PC running IAR is about the easiest development platform to get running in the entire industry. If you could get MSPGCC and CCS to work I assume your hardware was not faulty. Were you using one of the cracked copies of IAR which make the rounds in China? Some of those give trouble with some MSP430 devices.
I have yet to got it to work under MSP430, and how do I make MSP430G2553 run off external 16MHz or 24MHz crystal?
You can't get an MSP430G2553 to run at 24MHz. They only function up to 16MHz. If I remember correctly that device doesn't have the optional fast crystal oscillator. It only has a 32kHz crystal oscillator. You get fast clock rates from the internal DCO. Using a fast crystal generally defeats most of the ultra low power qualities of the MSP430, so few users actually want such an oscillator.
I pulled my copy of IAR off their website (painstakingly - SLOW!!) so I believe it is okay.

If I run my 2553 off the DCO @ 16MHz, how can I get a low tempco timing source?
« Last Edit: October 24, 2016, 09:04:12 am by technix »
 

Offline coppice

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Re: STC 8051 MCUs: yay or nay?
« Reply #22 on: October 24, 2016, 10:26:56 am »
If I run my 2553 off the DCO @ 16MHz, how can I get a low tempco timing source?
You can regularly recalibrate the DCO against a 32kHz crystal. There is at least one TI app note about doing that. You will never get super accurate results, as you can with the FLL in, say, the MSP430F4xx parts, but you can get sufficient stability for a wide range of applications.
 

Offline technix

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Re: STC 8051 MCUs: yay or nay?
« Reply #23 on: October 24, 2016, 12:48:07 pm »
If I run my 2553 off the DCO @ 16MHz, how can I get a low tempco timing source?
You can regularly recalibrate the DCO against a 32kHz crystal. There is at least one TI app note about doing that. You will never get super accurate results, as you can with the FLL in, say, the MSP430F4xx parts, but you can get sufficient stability for a wide range of applications.
Can I run the timer for millis() and delay() off the 32768Hz clock? I can live without micros() and delayMicrosecond() on smaller chips that implements simpler functionalities, and on bigger chips there will be a high frequency clock available.
 

Offline technix

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Re: STC 8051 MCUs: yay or nay?
« Reply #24 on: October 26, 2016, 04:00:24 am »
ST are competing heavily against STC in the Chinese market (are the names a coincidence?  >:D) by practically price-dumping on the STM8 range of chips.
STM8S003F3P6 gets advertised at under 1RMB, volume pricing might be slightly lower still.

And that's a much more modern, "sensible" design than the STC51 as far as I can see, with all the modern peripherals you'd expect, even 10bit ADC, of course on chip debugging, UART, I2C, SPI, ...

The cheapest model has 1KB of RAM and 8KB of Flash.

BTW I see the STM8 line much more commonly used on really low-cost Chinese products (like 10RMB LED controllers etc) than the STC line.

However there aren't too many teaching material out there targeting STM8 in China...
 


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