I/O Pins Used For Address/Data Multiplexed I/O Interface - Renesas H8SX/1650 Hardware Manual

6.9.4

I/O Pins Used for Address/Data Multiplexed I/O Interface

Table 6.19 shows the pins used for the address/data multiplexed I/O Interface.
Table 6.19 I/O Pins for Address/Data Multiplexed I/O Interface
When Byte
Control
SRAM is
Pin Specified
CSn CSn
AS/AH AH*
RD RD
LHWR/LUB LHWR
LLWR/LLB LLWR
D15 to D0 D15 to D0
A23 to A0 A23 to A0
WAIT WAIT
BS BS
RD/WR RD/WR
The AH output is multiplexed with the AS output. At the timing that an area is specified
Note: *
as address/data multiplexed I/O, this pin starts to function as the AH output meaning
that this pin cannot be used as the AS output. At this time, when other areas set to the
basic bus interface is accessed, this pin does not function as the AS output. Until an
area is specified as address/data multiplexed I/O, be aware that this pin functions as
the AS output.
Name I/O
Chip select Output
Address hold Output
Read strobe Output
Low-high write Output
Low-low write Output
Address/data Input/
output
Address Output
Wait Input
Bus cycle start Output
Read/write Output
Section 6 Bus Controller (BSC)
Function
Chip select (n = 3 to 7) when area n is specified as the
address/data multiplexed I/O space
Signal to hold an address when the address/data
multiplexed I/O space is specified
Signal indicating that the address/data multiplexed I/O
space is being read
Strobe signal indicating that the upper bytes (D15 to
D8) is valid when the address/data multiplexed I/O
space is written
Strobe signal indicating that the lower bytes (D7 to D0)
is valid when the address/data multiplexed I/O space
is written
Address and data multiplexed pins for the
address/data multiplexed I/O space.
Only D7 to D0 are valid when the 8-bit space is
specified. D15 to D0 are valid when the 16-bit space is
specified.
Address output pin
Wait request signal used when the external address
space is accessed
Signal to indicate the bus cycle start
Signal indicating the data bus input or output direction
Rev.2.00 Jun. 28, 2007 Page 191 of 666
REJ09B0311-0200