Toshiba TLCS-900/L1 Series Manual page 91

3.6.3 Connecting External Memory
Figure 3.6.6 shows an example of how to connect external memory to the TMP91C824.
In this example the ROM is connected using a 16-bit bus. The RAM and I/O are
connected using an 8-bit bus.
TMP91C824
CS 0
CS 1
CS 2
A0
to
A23
D8
to
D15
D0
to
D7
RD
WR
Figure 3.6.6 Example of External Memory Connection
(ROM uses 16-bit bus; RAM and I/O use 8-bit bus.)
A reset clears all bits of the port 6 control register P6CR and the port 6 function
register P6FC to 0 and disables output of the CS signal. To output the CS signal, the
appropriate bit must be set to 1.
TMP91C824FG
Figure 3.6.7 Example of External Memory Connection (RAM and I/O use 16-bit bus)
CS
Upper byte
ROM
OE
RD
WR
HWR
R/W
CS0
D [15:0]
Not connect
A0
A1
A2
A3
91C824-89
Address bus
CS CS
Lower byte 8-bit
ROM RAM
OE OE WE
16-bit SRAM
OE
LDS
74AC08
UDS
R/W
CE
I/O [16:1]
A0
A1
A2
TMP91C824
CS
8-bit
I/O
OE WE
2008-02-20