M16C65 Datasheet, PDF (205/829 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M16C/60

Under development
M16C/65 Group
Preliminary Specification
This is a preliminary specification and is subject to change.
11. Bus
11.3.5.4 Read and Write Signals
When the data bus is 16 bits wide, the read and write signals can be selected based on combinations
of RD, BHE, and WR, or combinations of RD, WRL, and WRH using the PM02 bit in the PM0 register.
When the data bus is 8 bits wide, use combinations of RD, WR, and BHE.
Table 11.6 shows Operation of the RD, WRL and WRH Signals. Table 11.7 shows Operation of the
RD, WR and BHE Signals.
Table 11.6 Operation of the RD, WRL and WRH Signals
Data Bus Width
RD
WRL
WRH
Status of External Data Bus
16-bit
L
H
H Read data
(BYTE pin input = low) _H
L
H Write 1 byte of data to an even address
H
H
L Write 1 byte of data to an odd address
H
L
L Write data to both even and odd addresses
Table 11.7 Operation of the RD, WR and BHE Signals
Data Bus
RD
Width
16-bit
H
(BYTE pin
L
input = low)
H
L
H
L
8-bit
H
(BYTE pin
input = high)
L
Note:
1. Do not use.
WR BHE A0
Status of External Data Bus
L
L
H Write 1 byte of data to an odd address.
H
L
H Read 1 byte of data from an odd address.
L
H
L Write 1 byte of data to an even address.
H
H
L Read 1 byte of data from an even address.
L
L
L Write data to both even and odd addresses.
H
L
L Read data from both even and odd addresses.
L
− ⁽¹⁾ H or L ^{Write 1 byte of data.}
H
− ⁽¹⁾ H or L ^{Read 1 byte of data.}
11.3.5.5 ALE Signal
The ALE signal is used to latch the address when a multiplexed bus space is accessed. Latch the
address at the falling edge of the ALE signal.
When BYTE pin input is high
ALE
When BYTE pin input is low
ALE
A0/D0 to A7/D7
Address
Data
A0
Address
When bits PM05 and PM04 are 01b or 10b (the multiplexed bus is either the CS2 or CS1 area)
A8 to A19
Address
A1/D0 to A8/D7
Address
Data
A9 to A19
When bits PM05 and PM04 are 11b (the entire CS area is the multiplexed bus)
A8
Address
Figure 11.3 ALE Signal, Address Bus, and Data Bus
Address
REJ09B0484-0030 Rev.0.30 Sep 09, 2008
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