HD6475348R Datasheet, PDF (39/487 Pages) Hitachi Semiconductor – Single-Chip Microcomputer

Table 1-4 Pin Functions (cont)
Pin No.
CP-84, FP-80A,
Type Symbol CG-84 TFP-80C I/O Name and Function
System BREQ 6
75
I Bus Request: Sent by an external device to the
control
H8/534 or H4/536 to request the bus right.
STBY 20
9
I Standby: A transition to the hardware standby
mode (a power-down state) occurs when a Low
input is received at the STBY pin.
RES
21
10
I/O Reset: Low input or low output due to watchdog timer
overflow causes the H8/534 or H8/536 chip to reset.
Address A19 – A8 54 – 43 41 – 30 O Address Bus: Address output pins.
bus
A7 – A0 40 – 33 28 – 21
Data bus D7 – D0 32 – 25 20 – 13 I/O Data Bus: 8-Bit bidirectional data bus.
Bus
WAIT 7
76
I Wait: Requests the CPU to insert one or more Tw
control
states when accessing an off-chip address.
AS
11
80
O Address Strobe: Goes Low to indicate that there
is a valid address on the address bus.
R/W
12
1
O Read/Write: Indicates whether the CPU is reading
or writing data on the bus.
• High—Read
• Low—Write
DS
13
2
O Data Strobe: Goes Low to indicate the presence
of valid data on the data bus.
RD
14
3
O Read: Goes Low to indicate that the CPU is
reading an external address.
WR
15
4
O Write: Goes Low to indicate that the CPU is
writing to an external address.
18