Datasheet
M32C/87 Group (M32C/87, M32C/87A, M32C/87B) 1. Overview
REJ03B0127-0151  Rev.1.51 Jul 31, 2008
Page 19 of 85
1.5 Pin Functions
Table 1.15 Pin Functions (100-Pin and 144-Pin Packages)
(1/4)
I: Input O: Output  I/O: Input and output
Type Symbol
I/O 
Type
Supply 
Voltage
Description
Power supply 
VCC1,VCC2
VSS
−−Apply 3.0 to 5.5 V to pins VCC1 and VCC2, and 0 V to the VSS pin. 
The input condition of VCC1 ≥ VCC2 must be met.
Analog power 
supply input
AVCC
AVSS
− VCC1 Power supply input pins to the A/D converter and D/A converter. 
Connect the AVCC pin to VCC1, and the AVSS pin to VSS.
Reset input RESET
I VCC1 The MCU is placed in the reset state while applying an “L” signal to 
the RESET
 pin.
CNVSS CNVSS I VCC1 This pin switches processor mode. Apply an “L” to the CNVSS pin 
to start up in single-chip mode, or an “H” to start up in 
microprocessor mode (mask ROM, flash memory version) and boot 
mode (flash memory version).
External data 
bus width 
select input
BYTE I VCC1 This pin switches a data bus width in external memory space 3. A 
data bus is 16 bits wide when the BYTE pin is held “L” and 8 bits 
wide when it is held “H”. Fix to either “L” or “H”.
Apply an “L” to the BYTE pin in single-chip mode.
Bus control 
Pins
D0 to D7 I/O VCC2 Data (D0 to D7) input/output pins while accessing an external 
memory space with separate bus.
D8 to D15 I/O VCC2 Data (D8 to D15) input/output pins while accessing an external 
memory space with 16-bit separate bus.
A0 to A22 O VCC2 Address bits (A0 to A22) output pins.
A23
O VCC2 Inverted address bit (A23) output pin.
A0/D0 to
A7/D7
I/O VCC2 Data (D0 to D7) input/output and 8 low-order address bits (A0 to 
A7) output are performed by time-sharing these pins while 
accessing an external memory space with multiplexed bus.
A8/D8 to
A15/D15
I/O VCC2 Data (D8 to D15) input/output and 8 middle-order address bits (A8 
to A15) output are performed by time-sharing these pins while 
accessing an external memory space with 16-bit multiplexed bus.
CS0
 to CS3 O VCC2 Chip-select signal output pins used to specify external devices.
WRL
/WR
WRH/BHE
RD
O VCC2
WRL, WRH, (WR, BHE) and RD signal output pins. WRL and WRH 
can be switched with WR
 and BHE by a program.
•WRL, WRH and RD are selected: 
If external data bus is 16 bits wide, data is written to an even 
address in external memory space while an “L” is output from the 
WRL
 pin. Data is written to an odd address while an “L” is output 
from the WRH
 pin. Data is read while an “L” is output from the 
RD
 pin.
•WR
, BHE and RD are selected: 
Data is written while an “L” is output from the WR
 pin. Data is 
read while an “L” is output from the RD
 pin. Data in odd address 
is accessed while an “L” is output from the BHE pin. Select WR, 
BHE
 and RD when an external data bus is 8 bits wide.
ALE O VCC2 ALE signal is used for the external devices to latch address signals 
when the multiplexed bus is selected.
HOLD
I VCC2 The MCU is placed in a hold state while an “L” signal is applied to 
the HOLD
 pin.
HLDA
O VCC2 The HLDA pin outputs an “L” while the MCU is placed in a hold 
state.
RDY
I VCC2 Bus is placed in a wait state while an “L” signal is applied to the 
RDY
 pin.










