AnsweredAssumed Answered

Communication between two STM32 devices via SPI interfaces (master/slave)

Question asked by omsker on Sep 16, 2014
Latest reply on Nov 4, 2014 by koldsoe.rasmus
I'm concerned with the communication between two stm32 devices via 4-wire SPI interface, no DMA, Keil RTX.

The first device (SPI master) is a base board with stm32f427, the secind device (SPI slave) is a display with stm32f207 (both our own hardware). The second device receives the voltage supply via the first device.

The problem is that the slave (display) starts up a little bit earlier (approx. 4--5 ms) than the master. This causes that the SPI interface of the slave is initialized before than the SPI interface of the master. The master sends data correctly, but these are not recognized by the slave (rx interrupt handler).

If I install a small delay before initializing the slaves, then everything is working properly.
Does anyone have any idea what exactly is the cause?