7 Host Interface Port
7 – 14
HSEL
HWR
HACK
ALE
HAD15–0
DATA
ADDRESS
HSEL
HRD
HACK
ALE
HAD15–0
ADDRESS
DATA
Host Write Cycle
Host Read Cycle
selects a multiplexed read/write select with data strobe, and HMD1
selects separate address and data buses. The timing for the read cycle and
the write cycle is as follows:
1.
The host asserts HRW and the address.
2.
The host asserts
HDS
and
HSEL
.
3.
The ADSP-21xx returns
HACK
(and, for a read cycle, the data).
4.
For a write cycle, the host asserts the data.
5.
The host deasserts
HDS
and
HSEL
.
6.
The host deasserts HRW and the address (and, for a write cycle, the
data).
7.
The ADSP-21xx deasserts
HACK
(and, for a read cycle, the data).
Figure 7.8 shows the HIP timing when HMD0=0 and HMD1=1. HMD0
selects separate read and write strobes, and HMD1 selects multiplexed
address and data buses. HD0-HD2 are used for the address. The timing
Figure 7.8 HIP Timing: Separate Strobes, Multiplexed Buses