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STP2002QFP
Fast Ethernet, Parallel Port, SCSI (FEPS) - STP2002QFP
Sun Microsystems,
buffers, it will be looped back to host memory. FAS366 is completely by-
passed during this operation.
As the prefetch buffers can store 128 bytes, 128 bytes will be moved from
the host memory to SCSI CE. After the DMA read is complete the 128 bytes
will be looped back to host memory, by a DMA write. Bit[2] of D_TST_CSR
register will program SCSI CE to be in DMA loop-back mode. Bit[3] of
D_TST_CSR register will indicate that loop-back is complete. The starting
address should be programmed at a 64-byte boundary.
For a programmer, the following will be the sequence of events.
1. Reset the SCSI CE.
2. Program the starting address in D_ADDR register.
3. Program the D_BCNT to 128 bytes.
4. Set the bit[2] of D_TST_CSR to select the loop-back mode.
5. Select DMA read (by writing to WRITE bit in D_CSR), Burst
Size should be programmed for 64B.
6. Enable DMA.
7. Wait for interrupt.
8. After the interrupt, look at bit[3] of D_TST_CSR.
9. If the bit[3] is set, 128 bytes of data from host memory has been
moved into the prefetch buffers.
10. Reset the SCSI CE.
11. Program the starting address in D_ADDR reg, this is the address
where data coming out to prefetch buffers, will be written in host
memory.
12. Program the D_BCNT to 128 bytes.
13. Set the bit[2] of D_TST_CSR.
14. Select DMA write (by writing to the WRITE bit in CSR), Burst
Size should be programmed for 64 bytes.
15. Enable DMA.
16. Wait for interrupt.
17. After the interrupt, look at bit[3] of D_TST_CSR.
18. If this bit is set, 128 bytes from the prefetch buffers have been
written back to the host memory.