So there is a Cortex-M OTP MCU...

[technix]

MindMotion MM32P020 series. 4KB OTP ROM, 128 bytes SRAM, Cortex-M0 core, 5V operation.

128 bytes SRAM...

[JPortici]

Wow, zero hits on google.

By the way, what advantages do we have with OTP memory over flash memory?
If i had to make a guess i would say increased reliability, with also lower cost..
does OTP memory not suffer from data retention loss, as flash memory does?

[Kjelt]

Depends how they implemented the OTP memory.
If it is the same process but updated as proms (you know eproms without uv transparant glass window) that in fact have small capacitors that hold the charge but will leak over time, you will still have data retention loss. It all depends how good they have made the isolation layers and how big the capacitors in that case.
If they implemented it as fuses you won't have this problem.
The third option is the most feasible IMO that it is just flash memory but without the possibility to erase it (eg disabled or missing boostconverter for the higher erase voltage) so the retention times will be the same as the other modern flash products which is pretty good.

[westfw]

An arm with 128bytes of ram sounds awful.

[SiliconWizard]

An arm with 128bytes of ram sounds awful.

Pretty much. And just 4KB of ROM space? But I'm sure there are still a few applications.

Would technix happen to have any link or documentation? Zero hit on all search engines I tried.
I guess this is yet another very low-cost chinese MCU? I'm amazed at how creative and productive they can be when it comes to developing such low-cost, to-the-point products. Even though *we* often don't see the point, I'm sure *they* perfectly do.

[technix]

An arm with 128bytes of ram sounds awful.

Pretty much. And just 4KB of ROM space? But I'm sure there are still a few applications.

Would technix happen to have any link or documentation? Zero hit on all search engines I tried.
I guess this is yet another very low-cost chinese MCU? I'm amazed at how creative and productive they can be when it comes to developing such low-cost, to-the-point products. Even though *we* often don't see the point, I'm sure *they* perfectly do.

Yes it is Chinese and I only have links to Chinese documentation.

Datasheet: http://www.mindmotion.com.cn/userfiles/images/MM32P0XiLieWenDang/DS_MM32P021_Ver1.9.0.pdf
User manual: http://www.mindmotion.com.cn/userfiles/images/MM32P0XiLieWenDang/UM_MM32P021_m_V1.51_SC.pdf

[bson]

Do they have a 3.3V version?  Any info on power consumption when run off a 32kHz low power watch crystal at a 200-400kHz CPU clock or so?

[technix]

Do they have a 3.3V version?  Any info on power consumption when run off a 32kHz low power watch crystal at a 200-400kHz CPU clock or so?

The datasheet claims that it can work anywhere from 2.5V to 5.5V. There is no power draw data n their datasheet.

[SiliconWizard]

Do they have a 3.3V version?  Any info on power consumption when run off a 32kHz low power watch crystal at a 200-400kHz CPU clock or so?

The datasheet claims that it can work anywhere from 2.5V to 5.5V. There is no power draw data n their datasheet.

Well, I don't speak chinese, but on page 9 there is a "DC" table where there are figures which look like power draw (IDD) figures for various conditions, but I can't really understand the details
Could you help?

[technix]

Do they have a 3.3V version?  Any info on power consumption when run off a 32kHz low power watch crystal at a 200-400kHz CPU clock or so?

The datasheet claims that it can work anywhere from 2.5V to 5.5V. There is no power draw data n their datasheet.

Well, I don't speak chinese, but on page 9 there is a "DC" table where there are figures which look like power draw (IDD) figures for various conditions, but I can't really understand the details
Could you help?

Maximum currents:
Full speed: 7.2/2.34mA (7.2mA under 5V, 2.34mA under 3.3V) at 25 degrees Celsius.
Sleep mode: 14.84/1.86mA over -40 to +85 degrees Celsius
Stop mode: 8.0/7.0uA over -40 to +85 degrees Celsius