HD6432621 Hitachi, HD6432621 Datasheet - Page 181

• Manufacturer Part Number: HD6432621
• Description: (HD64F262x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

7.1.3
Table 7-1 summarizes the pins of the bus controller.
Table 7-1
Name
Address strobe
Read
High write
Low write
Wait
Bus request
Bus request
acknowledge
Bus request output
Pin Configuration
Bus Controller Pins
Symbol
AS
RD
HWR
LWR
WAIT
BREQ
BACK
BREQO
I/O
Output
Output
Output
Output
Input
Input
Output
Output
Function
Strobe signal indicating that address output on address
bus is enabled.
Strobe signal indicating that external space is being
read.
Strobe signal indicating that external space is to be
written, and upper half (D15 to D8) of data bus is
enabled.
Strobe signal indicating that external space is to be
written, and lower half (D7 to D0) of data bus is enabled.
Wait request signal when accessing external 3-state
access space.
Request signal that releases bus to external device.
Acknowledge signal indicating that bus has been
released.
External bus request signal used when internal bus
master accesses external space when external bus is
released.
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