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Specific data send to Bigfoot Killer 2100 memory gets dropped by MPC8314E's CSB PCIe Bridge #2

@DvdBoon

Description

@DvdBoon

Specific data send by the 68K to Prometheus over the PCIe bridge to the PCIe Bigfoot card gets dropped.

This is not address specific but data specific and 100% reproducable.

The following error bit is flagged: PEX_CSB_IBSTAT_BRGER = 1

For byte transfers, the following data is lost and the MPC8314E indicates an error on CSB inbound transfer (tested from $00-$C0, i guess I should test till $FF):

$31, $32, $34, $37, $38, $3B, $3D, $3E

Word transfers and longword transfers are harder to predict which ones get dropped, but at least a very vital longword gets dropped which is used in the reset procedure:

$52535445

Old data remains in the memory location the write was supposed to go. It does not lock the card and data can be continued to be send.

Another example; At a location the inital data is 0,0,0,0 in longwords. Writing the following longwords:

$806001E4, $38630001, $906001E4, $4BFFFFF4

Gives the following result:
$806001E4, $00000000, $906001E4, $4BFFFFF4

With further tests just writing $38630001 anywhere in the address range, the results are always that this longword gets dropped with a CSB inbound error.

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