Texas Instruments TMS320C6201 Reference Manual page 224

Expansion Bus Host Port Operation
8-30
5) Data phase: The external device is not ready to deliver data, as indicated
by XRDY high.
6) Same as 5.
7) Same as 5.
8) Same as 5.
9) The external device presents requested data (D1), and asserts XRDY.
10) The external device is not ready to deliver next data. The XRDY is ne-
gated.
11) Same as 10
12) Same as 10
13) The external device presents next data (D2), and asserts XRDY.
14) The external device presents next data (D3), and XRDY stays asserted.
15) The external device presents next data (D4), and XRDY stays asserted.
16) The external device presents next data (D5), and XRDY stays asserted.
The DSP can not accept the new data (D5), and asserts XWAIT.
17) The external device recognizes XWAIT, and keeps the D5 on the expan-
sion bus. The XRDY is asserted and indicates that the external device is
ready waiting for the DSP to accept the data.
18) The DSP deasserts XWAIT,, and accepts D5.
19) The external device presents next data (D6), and XRDY stays asserted.
20) The external device presents next data (D7), and XRDY stays asserted.
21) The external device presents the last data (D8), and the 'C6202 asserts
the XBLAST.
22) The recovery cycle.
23) The DSP negates the expansion bus request (XHOLD), and turns off the
outputs.