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BF533 SPI boot problem - has anyone experienced this strange behavior?

Question asked by van on Dec 28, 2010
Latest reply on Mar 24, 2011 by van

I have a new target board that uses bmode = 11, boot from SPI slave. I am able to read the 24 bit SPI flash perfectly with my code using the SPI port controller and polling for bytes, but the BF533 won't boot from that same device.

 

The boot sequence starts correctly, sending the 03 read command and three address bytes. The flash responds with the 0x40.

The dsp toggle PF2 (/cs) and repeats the above. The flash responds with the entire first block 40 00 80 ff 04 00 00 00 12 00.

The dsp does another read, this time specifying address 0x0e. The flash replies with fc 02 07 f8 .... (essentially garbage) and the stranger thing is that the 1 to 0 transition in the first byte occurs on the rising edge of SPI_CLK. After receiving garbage, the dsp gives up and ends the boot sequence.

 

CLK is pulled down, MISO is pulled up. And both are quiet signals.

This is repeatable on multiple boards and using 3 different brands of serial flash, all derivatives of the 25L40 series

 

I'm fairly certain that the other SPI devices on the same bus are not interfering (at least their /cs signals remain high throughout the boot process).

I'm using a reset IC so I don't think it's a power up glitch problem.

 

Does anyone have any ideas where to look next...it's been 5 days and I'm at a total loss.

 

Many thanks

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