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SPI interface in MC9S12GC32

Question asked by shivdas dhongade on Aug 12, 2008
Latest reply on Aug 16, 2008 by David Payne
I'm using an SPI interface in processor MC9S12GC32  to interface a serial EEPROM. I have configured the SPI inetrface as per the guidelines provided by interface documents. In my application, I'm sending a command to read data byte from a specific address of the memory chip. All the necessary signals viz, chip select, clock, MOSI etc are generated properly (as per the signal levels/frequency provided by chip manufacturer) but there is no data placed on MISO by the memory chip. If we access the chip using general purpose I/O, data read / write is perfectly working.
It is observed that after sending 3 bytes (command byte and 2 bytes of address) on MOSI, SPI controller of the processor deselects the chip and clock is also stopped. What could be the reason for this behaviour of SPI controller?? After sending 3 bytes, it is expected that memory chip shall send the data byte on MISO. Can anybody help?