[U-Boot-Users] SPI EEPROM problem on MBX (looping MISO and MOSI works)

Antonio Di Bacco antonio.dibacco at aruba.it
Sat Mar 18 22:20:40 CET 2006

I'm trying to make a work an SPI EEPROM (I tried with an AT25HP512 and an 
AT25256) connected to the expansion connector 
of an old MBX board featuring  MPC860EN processor. I used the spi.c driver in 
u-boot patched from Gurevitch but 
nothing. Could I have problems with relocation of DPRAM for SPI? but I think 
this handled automatically. I simply defined CFG_SIMPLE_SPI_WRITE, CONFIG_SPI 
and CONFIG_SPI_X and it should be enough.

I double checked all the connections to the SPI EEPROM and they seem ok, when 
configuring the SPIMISO, SPIMOSI, SPICLK and SPISEL as GPIO active output I 
can measure a right voltage level on these pins when I write something to 
Port B data register. Unfortunately I have a not an oscilloscope to see what 
happen when I use the sspi command like this:

sspi 0 8 05   (with Gurevitch patch)
 05 is the code to read a configuration register.

Sometimes the EEPROM answer FF, some others 00 , it is completely randomic.

I found that looping the SPIMISO and SPIMOSI with an external electric loop 
gives the right behaviour, I receive what I send. Anyone can help? 


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