AnsweredAssumed Answered

Peculiar behaviour of SPI MOSI line on STM32F3xx. MOSI line remain up after transmission

Question asked by casamassima.filippo on Jan 17, 2014
Latest reply on Jan 22, 2014 by casamassima.filippo
Hi all, 
I'm tryng to use SPI in half-duplex mode on STM32F303VC microcontroller.
The STM32 act as Master.
MOSI line is used as data line for input and output.

In my setup I have to send an address register using MOSI line and then read data trough the same line (peripheral is in half duplex) 
the problem is that after sending one byte, the MOSI line remains at high logical level.. This is not an issue when I need to send multiple data, as shown in figure transmission is fine. 
The problem is that when I switch to read mode 
SPI_BiDirectionalLineConfig(SPI2, SPI_Direction_Rx);
the MOSI line is still up and corrupt the data (second figure)SPI%20MOSI%20line_small.jpg