7
Host Interface Port
7 –
15
for the read cycle and the write cycle is as follows:
1.
The host asserts ALE.
2.
The host drives the address.
3.
The host deasserts ALE.
4.
The host stops driving the address.
5.
The host asserts (
HRD
or
HWR
) and
HSEL
.
6.
The ADSP-21xx returns
HACK
(and, for a read cycle, the data).
7.
For a write cycle, the host asserts the data.
8.
The host deasserts (
HRD
or
HWR
) and
HSEL
.
9.
For a write cycle, the host deasserts the data.
10. The ADSP-21xx deasserts
HACK
(and, for a read cycle, the data).
Figure 7.9 shows the HIP timing when HMD0=1 and HMD1=1. HMD0
selects a multiplexed read/write select with data strobe, and HMD1
selects multiplexed address and data buses. HD0-HD2 are used for the
address. The timing for the read cycle and the write cycle is as follows:
HSEL
HDS
HACK
HRW
ALE
DATA
HAD15–0
ADDRESS
HAD15–0
ADDRESS
DATA
HSEL
HDS
HACK
HRW
ALE
Host Write Cycle
Host Read Cycle
Figure 7.9 HIP Timing: Multiplexed R/W Strobe, Multiplexed Buses