Fujitsu MHU2100AT manual Ultra DMA Feature Set

5.5 Ultra DMA Feature Set

b)Device terminating an Ultra DMA data out burst

The following steps shall occur in the order they are listed unless otherwise specifically allowed (see 5.6.3.11 and 5.6.3.2 for specific timing requirements):

1)The device shall not initiate Ultra DMA burst termination until at least one data word of an Ultra DMA burst has been transferred.

2)The device shall initiate Ultra DMA burst termination by negating DDMARDY-.

3)The host shall stop generating an HSTROBE edges within tRFS of the device negating DDMARDY-.

4)If the device negates DDMARDY- within tSR after the host has generated an HSTROBE edge, then the device shall be prepared to receive zero or one additional data words. If the device negates DDMARDY- greater

than tSR after the host has generated an HSTROBE edge, then the device shall be prepared to receive zero, one or two additional data words. The

additional data words are a result of cable round trip delay and tRFS timing for the host.

5)The device shall negate DMARQ no sooner than tRP after negating DDMARDY-. The device shall not assert DMARQ again until after the Ultra DMA burst is terminated.

6)The host shall assert STOP with tLI after the device has negated DMARQ. The host shall not negate STOP again until after the Ultra DMA burst is terminated.

7)If HSTROBE is negated, the host shall assert HSTROBE with tLI after the device has negated DMARQ. No data shall be transferred during this assertion. The device shall ignore this transition of HSTROBE. HSTROBE shall remain asserted until the Ultra DMA burst is terminated.

8)The host shall place the result of its CRC calculation on DD (15:0) (see 5.5.5).

9)The host shall negate DMACK- no sooner than tMLI after the host has asserted HSTROBE and STOP and the device has negated DMARQ and

DDMARDY-, and no sooner than tDVS after placing the result of its CRC calculation on DD (15:0).

10)The device shall latch the host's CRC data from DD (15:0) on the negating edge of DMACK-.

11)The device shall compare the CRC data received from the host with the results of its own CRC calculation. If a miscompare error occurs during one or more Ultra DMA bursts for any one command, at the end of the command, the device shall report the first error that occurred (see 5.5.5).

12)The device shall release DDMARDY- within tIORDYZ after the host has negated DMACK-.

C141-E202-01EN 5-143