Tag Archives: SPI

Adding DMA to the SPI driver with the STM32F4

By | March 11, 2012

Sending data over SPI with the STM32 using polling is simple and reliable but your processor is blocked, unable to do anything else until the transfer is complete. Direct Memory Access (DMA) allows you to initiate a transfer of a block of data and then carry on doing something else while that completes. At the… Read More »

Decimus hardware fix

By | February 23, 2008

It was all getting too awkward. A bit of short sighted design on my part had the Nokia LCD sharing an SPI port with the motor encoders. This meant that I had to turn off the encoders to write to the LCD. While no motion information would be lost by doing this, it effectively meant… Read More »

LS7366 quadrature counter

By | February 21, 2008

The LS7366 is a 32 bit counter with a direct interface for quadrature signals from incremental encoders. There is also an index channel for marker functions. The interface to the microcontroller is SPI mode 0 making it relatively easy to drive with a variety of common controllers. Decimus has one of these on each motor… Read More »

SPI data transfers

By | February 21, 2008

I use SPI  on my micromouse both to talk to the Nokia graphical LCD and to talk to the LS7366 quadrature encoders. A large number of devices can be connected to the SPI data lines, MOSI and MISO. Each device needs its own select line. This all appear very simple and friendly. There is, however… Read More »