External Bus; Input/Output Pins - Renesas H8SX/1650 Hardware Manual

Section 6 Bus Controller (BSC)
6.5

External Bus

6.5.1

Input/Output Pins

Table 6.2 shows the pin configuration of the bus controller and table 6.3 shows the pin functions
on each interface.
Table 6.2 Pin Configuration
Name
Bus cycle start
Address strobe/address hold
Read strobe
Read/write
Low-high write/lower-upper
byte select
Rev.2.00 Jun. 28, 2007 Page 150 of 666
REJ09B0311-0200
Symbol I/O
BS
Output
AS/AH
Output
RD
Output
RD/WR Output
LHWR/LUB Output
Function
Signal indicating that the bus cycle has
started
•
Strobe signal indicating that the basic
bus, byte control SRAM, or burst ROM
space is accessed and address output
on address bus is enabled
•
Signal to hold the address during
access to the address/data multiplexed
I/O interface
Strobe signal indicating that the basic bus,
byte control SRAM, burst ROM, or
address/data multiplexed I/O space is
being read
•
Signal indicating the input or output
direction
•
Write enable signal of the SRAM during
access to the byte control SRAM space
•
Strobe signal indicating that the basic
bus, burst ROM, or address/data
multiplexed I/O space is written to, and
the upper byte (D15 to D8) of data bus
is enabled
•
Strobe signal indicating that the byte
control SRAM space is accessed, and
the upper byte (D15 to D8) of data bus
is enabled