M16C30P_07 Datasheet, PDF (53/317 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/30 SERIES

M16C/30P Group
7. Bus
7.2.4 Read and Write Signals
When the data bus is 16 bits wide, the read and write signals can be chosen to be a combination of RD, BHE
and WR or a combination of RD, WRL and WRH by using the PM02 bit in the PM0 register. When the data
bus is 8 bits wide, use a combination of RD, WR and BHE.
Table 7.2 shows the Operation of RD, WRL, and WRH Signals. Table 7.3 shows the Operation of RD, WRL,
and BHE Signals.
Table 7.2 Operation of RD, WRL and WRH Signals
Data Bus Width
RD
16-bit
L
(BYTE pin input = L) _H
H
H
WRL
H
L
H
L
WRH
H
H
L
L
Status of External Data Bus
Read data
Write 1 byte of data to an even address
Write 1 byte of data to an odd address
Write data to both even and odd addresses
Table 7.3 Operation of RD, WRL and BHE Signals
Data Bus Width _RD
16-bit
H
(BYTE pin input = L) _L
H
L
H
L
8-bit
H
(BYTE pin input = H) _L
WRL
L
H
L
H
L
H
L
H
BHE
L
L
H
H
L
L
Not used
Not used
A0
H
H
L
L
L
L
H or L
H or L
Status of External Data Bus
Write 1 byte of data to an odd address
Read 1 byte of data from an odd address
Write 1 byte of data to an even address
Read 1 byte of data from an even address
Write data to both even and odd addresses
Read data from both even and odd addresses
Write 1 byte of data
Read 1 byte of data
7.2.5 ALE Signal
The ALE signal latches the address.
Rev.1.22 Mar 29, 2007 Page 37 of 291
REJ09B0179-0122