Figure 4-6 Coprocessor Connections With Unidirectional Bus - ARM ARM7TDMI Technical Reference Manual

4.5.2 Connecting multiple coprocessors
ARM DDI 0210C
ARM core

Figure 4-6 Coprocessor connections with unidirectional bus

The logic for Figure 4-6 is as follows:
on FALLING MCLK
ASEL = ((nMREQ = 1 and SEQ = 1) and (not nRW))
CSEL = ((nMREQ = 1 and SEQ = 1) and (nRW))
If you have multiple coprocessors in your system, connect the handshake signals as
follows:
nCPI Connect this signal to all coprocessors present in the system.
CPA and CPB
The individual CPA and CPB outputs from each coprocessor must be
ANDed together, and connected to the CPA and CPB inputs on the
ARM7TDMI processor.
You must multiplex the output data from the coprocessors.
Connecting multiple coprocessors is shown in Figure 4-7 on page 4-14.
Copyright © 2001, 2004 ARM Limited. All rights reserved.
ASEL
0
DIN
1
DOUT
CSEL
0
1
CPDIN
Coprocessor
Coprocessor Interface
Memory
system
0
1
CPDOUT CPDRIVE
4-13