7
Host Interface Port
7 –
13
HMD0 selects separate read and write strobes, 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 the address.
2.
The host asserts (
HRD
or
HWR
) 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 (
HRD
or
HWR
) and
HSEL
.
6.
The host deasserts the address (and, for a write cycle, the data).
7.
The ADSP-21xx deasserts
HACK
(and, for a read cycle, the data).
Figure 7.7 shows the HIP timing when HMD0=1 and HMD1=0. HMD0
HD15–0
DATA
HSEL
HDS
HACK
HA2–0
ADDRESS
HRW
HSEL
HDS
HACK
HA2–0
ADDRESS
HRW
HD15–0
DATA
Host Write Cycle
Host Read Cycle
Figure 7.7 HIP Timing: Multiplexed R/W Strobe, Separate Buses