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Trying to use the io-expander MCP23S17 with BF516F

Question asked by kentatmotion on Apr 19, 2011
Latest reply on Apr 19, 2011 by WassimB

Hi

 

We seem to have a little problem using the mcp23s17 from microchip with our bf516f. The ioexpander seem to need to have the SCK and CS low while it receive the read command and also when the command is issued becouse it is sending the data directly after the command.

 

We are sending the read command to get the values on the gpio pins on the mcp23s17 and it has 2 blocks of 8 st gpio pins and we can see that we get the MSB of each block but we think that becouse of the SCK getting inactive after the command, we seem to miss the other 7 bits that the mcp23s17 wants to send. Also it does not hold the data so we cant get it in the next clock burst.

 

Is there any way to keep SCK active on SPI1 for a period more then 8 or 16 bits? 

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