Electronic – use mbed for STM32F103(C8T6)

mbedstm32

I have some experience with Arduino, but for one of the devices I want to use something with more power (RAM/CPU power).

I already found out that some STM32F4 or STM32F7 models really with what I need, however, since I have no experience, I bought a (very cheap) STM32F103C8TT6 evaluation board.

I don't have it yet, but I'm reading information about it. I encountered mbed which seems a very easy way to program it.

However, in the list of boards I don't see any evaluation boards, mostly NUCLEO's or Discovery versions.

Is it possible to still use it? (like by selecting the 'similar'NUCLEO F103RB' or is mbed only supporting NUCLEO's (and lots of other ARM core devices) ?

The reason is that if the evaluation board does not support mbed, it's not really a good alternative to try if I can use mbed later anyway on the actual STM32 version I want.

Best Answer

Yes, you can. You can create a new project based on NUCLEO F103RB and then replace precompiled library with sources. Then in sources you can redefine pin mappings to fit your specific board. Please note, that I haven't done this for STM MCUs, but ~2 years ago I got it working for my nRF51 custom board.

The idea is, that MCU stays the same with all the internal peripherals, you just have pins wired slightly differently. Additional changes might be required if your board has different clock source.

Related Solutions

How to connect an Arduino to a STM32F4 evaluation board

The easiest solution would most likely involve an I2C connection between the two boards. I'm not familiar with the EtherMega, but I know the STM32F4-Discovery has several I2C pins available. You could then let the Arduino handle the network protocol, and only shift the relevant information over to the STM. Whether or not this will be fast enough for your purpose, I cannot say.

The only thing you need in terms of extra components is a way of level-shifting the (presumably) 5V of the Arduino to the 3.3V of the STM32F4-Discovery. For I2C a simple solution is to use an n-channel mosfet with two pull-up resistors per line (SDA, SCL - so 2 mosfets and 4 resistors in total). Philips/NXP has a very nice application note on this, specifically for I2C, available here:

http://ics.nxp.com/support/documents/interface/pdf/an97055.pdf

STM32F103 strange behavior

I may have figured this out. I have been using ST standard peripheral library to configure and use the SPI and DMA controllers (among others). I noticed that the SPI configuration registers were inconsistent depending on the declaration of variables at the start of main(). As an experiment I set the SPI config registers explicitly, eg as SPI1->CR1 = 0b0000100100110011. And everything works fine! I'm honestly still a bit confused as to why this might be a problem. I have been setting up the ST code as such: Under main() I declare

SPI_InitTypeDef     SPI_InitStructure;

Then further on down the track I initialise the SPI peripheral

SPI_I2S_DeInit(SPI1);
SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI_InitStructure.SPI_Mode = SPI_Mode_Slave;
SPI_InitStructure.SPI_DataSize = SPI_DataSize_16b;  //SPI_DataSize_8b; 
SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;                     // SCK idle high
SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;                    // second transition -> SCK Idle high => capture on rising edge of clock
SPI_InitStructure.SPI_NSS = SPI_NSS_Hard;                       // SS must be low during entire SPI transaction
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;                
SPI_Init(SPI1, &SPI_InitStructure);

But still there are shenanigans. Anyway, I will update if I make any more discoveries. I think I might abandon the ST peripheral library for initialisation, etc. Thanks again

Best Answer

Related Solutions

How to connect an Arduino to a STM32F4 evaluation board

STM32F103 strange behavior

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