Interesting microcontrollers from China no one heard about - how to use them?

[brucehoult]

the stm32f030f4p6 (probably a clone) can be had for $0.3 from taobao... it is cortex-m0 @ 48MHz and has 4KB ram and 16KB flash.

Does that have any memory that can hold program variables while the power is off? Like the EEPROM on an AVR. Can a running program write to the flash?

[mikeselectricstuff]

the stm32f030f4p6 (probably a clone) can be had for $0.3 from taobao... it is cortex-m0 @ 48MHz and has 4KB ram and 16KB flash.

Does that have any memory that can hold program variables while the power is off? Like the EEPROM on an AVR. Can a running program write to the flash?

Are there any flash micros today that can't write their own flash?
Flash can be less than ideal for param storage due to page sizes & endurance, but usually manageable if minimum cost is your goal.
External eeproms aren't exactly expensive -several under 5 cents at qty 1k at Digikey

[brucehoult]

the stm32f030f4p6 (probably a clone) can be had for $0.3 from taobao... it is cortex-m0 @ 48MHz and has 4KB ram and 16KB flash.

Does that have any memory that can hold program variables while the power is off? Like the EEPROM on an AVR. Can a running program write to the flash?

Are there any flash micros today that can't write their own flash?

No idea, I only have experience of a tiny subset of all microcontrollers made, which is why I asked.

[coppice]

Are there any flash micros today that can't write their own flash?

Depends what you mean by "write their own flash". Quite a few MCUs require an external high voltage, as the die area needed for a charge pump has been saved. Many require a complex protocol on the JTAG port, with fairly precise timing, in order to program the flash. Many which can do their own programming just by being supplied with the necessary data require software loaded into them to be able to do this - e.g. a JTAG port is used to load the programming code into RAM, or an initial JTAG controlled programming sequence gets the programming code into one segment of flash, from which the other segments of flash can be programmed just by feeding the MCU the data.

You might expect savings to only be made on small devices, but some big complex automotive MCUs lack the internal charge pump. This might possibly be a safety issue - ensuring the code can never change accidentally in the field, if the MCU gets kicked into an unfortunate mode. This is a common cause of corrupt flash MCUs when complete internal control of the flash is provided. Quite a few projects need their code updated for this kind of problem, when returns from the field flood in. 

When you look at things like FRAM density versus flash density, the high voltage charge pump is a big factor. Its a large overhead when the flash is small, but a small overhead when the flash is large. This is why you see things like TI focusing its FRAM efforts on smaller MCUs.

[Mr. Scram]

Though I don't have any practical use for cheap and possibly dubious microcontrollers, I totally understand the fascination with slightly exotic microcontrollers that come are at the extreme of what the industrial world can produce.

[romhunter]

Call me crazy but I ordered an ICE for the Padauk-uCs yesterday 

I know this thread is quite old but did you received it yet?
I'm interested in those 4 bitters too.

[moeabode@netzero.com]

Well, maybe a long shot but here goes; anyone have firmware for    PMS131-S14 PADAUK ? prototype that was made in China used this micro controller . They said they don't have firmware which causes a big issue when using same chip and mass producing
Thanks in advance, regardles