ChibiOS Free Embedded RTOS

Here the patch to use SPI in slave mode on the STM32F1x (but I think should work alson on F4).

--- spi_lld.c 2012-06-18 19:14:28.000000000 +0200
+++ /home/formica/chibios/chibios/os/hal/platforms/STM32/spi_lld.c 2013-04-10 12:21:44.096847872 +0200
@@ -294,10 +294,16 ...

Dear all,
I'm developing the FreeCopter project using ChibiOS on STM32F1, and I'd like to share with you the code also because I succeed to build an SPI Master/Slave communication... could be interesting for someone because there is no official support for the SPI SLAVE in Chibios.

The code is on ...

Yes, I'm running with all the DEBUG options activated.

I'm using that rule, deactivating everything and re-introducing the peripherals one by one... but still I don't understand what exactly goes wrong!

My last version: I added a control on the USB_STATE.
As before, sometimes, when I don't read the USB from the terminal, the SPI hangs up.

Any idea?


systime_t time = chTimeNow(); // T0
while (TRUE) {

time += MS2ST(25); // Next deadline
// bmp085_read_temp();
// bmp085_read_press(BMP_MODE_PR0 ...

I'm using an STM32F103RBT6!
I don't know what is a CCM memory (maybe an external ram). In this case... no, I'm just using a raw stm32f103rbt6 with some sensors on the I2C bus (gyro,acc,magn).
I attach the main file (with a lot of comments inside... It's a very dirty piece of code, sorry).
Now usb ...

I discovered that the problem exists when, in the main thread, I use the serial-usb. It seems that SPI and SerialUsb cannot co-exist. If I move the spi in another thread... everything is ok. It sounds really strange!

Thanks giovanni for your quick response. Also using your correction I obtain the same behavioe. The main thread doesn't communicate through spi. I'm chechking with the oscilloscope everytime.

I observe a strange behavior traying to use the SPI on my custom board:


cRPY_16bit[0] = 128;
cRPY_16bit[1] = 128;
cRPY_16bit[2] = 128;
cRPY_16bit[3] = 128;
cRPY_16bit[4] = 128;

spiAcquireBus(&SPID2); /* Acquire ownership of the bus. */
spiStart ...

Dear all,
I'm a little bit confused about the SPI API. Reading the documentation there are some function used for a syncronous communication and others for asyncronous one.
I know that that the SPI protocol has a dedicate clock line so it is intrinsically syncronous.
So, what does it means ...

I confirm that using also the jsnyder toolchain the problem is solved.
But still we don't know why.

formica

P.S. Thx tectu. I found the gcc-arm-embedded sources for linux... but not the precompiled bins. Can you help me?