Looking for an MCU reference

[neoirto]

Posted on July 23, 2013 at 10:24

Hi all,

I had good experiences on STM32F4 peripherals, but I'm new to ST 8 bits family, so I'd like your feedback and help to match a good MCU at lower cost possible, and that could match that features :- 3.3V operations- USB data transfer at High or moderate speed (cost first), with a mass storage declaration (new to that too), and with firmware flashing capability by USB : is there any library/example I can start with for that purpose ?- 2 peripherals on SPI with DMA : 1x for a peripheral read operation (20 MHz capable), and one for �SD r/w : write at continuous minimum 112 Kb/s with reliability, but 896 Kb/s capable would be perfect. I planned to do it with Fats fs library. Perhaps I will need 2 DMA for that ?That point is critical because of the RAM usage... I just don't know if it's possible on an 8 bits MCU... In fact I just need to read datas on SPI, save it somewhere (with 2Gb  max)... And in another mode, transfer that datas to PC via USB.- 1x i2c at 400 kHz (interrupt mode or DMA+int).- Standby mode with low power (ultra low prefered but not critical).- 1x 16 bits Timer, a few EXTIO...- a few eeprom...What do you think about this requirements ? Is it possible with 8 bits family ?Thanks in advance for your answers #usb-sd-spi-dma

[fggnrc2]

Posted on July 23, 2013 at 15:55

Hello stephane!

The answer to your question is NO, because there is no STM8 microcontroller that natively supports USB. If you give up to USB links, there may be a part that suits your needs. Regards EtaPhi

[neoirto]

Posted on July 23, 2013 at 16:58

Thanks for your answer EtaPhi,

Well, I will need USB, so I have to take a look at STM32... I'm afraid of.But I'm curious to see the cost gap between High end STM8 and Low prices STM32... Could you please give us the reference ?Tx again 😉

[fggnrc2]

Posted on July 23, 2013 at 17:40

Well, the cheapest STM32 I can find on ST site is STM32F030F4P6 and it costs 0.425 dollars each if you buy 10k parts.

On the STM8 side, a similar feature part is STM8L051F3P6 and it costs 0.385 dollars each if you buy 10k parts. As you see, the price difference is small...

[neoirto]

Posted on July 23, 2013 at 19:01

That's an interesting point,

I take a look at STM32 references and I believe 

http://www.st.com/web/en/catalog/mmc/FM141/SC1169/SS1295/LN962/PF252049

 could be a good candidate for me. It may be the lowest cost MCU that supports USB I presume ?If I use SDIO instead SPI, I will save money for the extra RAM needed for SPI operations.But this MCU appears to support bootloader via USART, not USB.So is it possible to upload to SD card, and then flash the program instead of live flashing via USB ?I will probably have to create another thread !