hi, we are trying to interface At25256AW to LPC3250 on SPI port 1.Following is the hardware configuration:
WP pin is high
SPI1_DATAIO connected to SI pin
SPI1_DATAIN connected to SO pin (This in is pulled highso that we can boot the code from it )
nhold pin pulled high
SPI1_ssel connected to ncs
Problem we are facing is that ,data read is 0.
Following is the procedure we followed we first give WREN Command then Read the status Register
1) We gave WREN to EEPROM
2) then we gave a dummy write(0x55)
3) then we read the SPI_data register ,the value is 0
Scope observation
If we probe SO pin ,there is a data other than Zero ,but controller is unable to read it. We have changed the controller to receiver module after dummy write(step 2) and before start reading data(Step 3).
If we probe SI and SO Pin togather,on SO pin we first see 0x06 and 0x55, on SI pin we are seeing data Exactly at time when we see data 0x55 0n SO pin.
From this it looks Transmitter module is still on,what we are feeling is that data shouldn't come out of Controller during Dummy Write.
What can be the problem.
Regards Sumit
hi,
I am waiting for some reply from Forum,if any further inputs are required please let me know.
Thanks & Regards Sumit