RA8806
Preliminary Version 1.0
Two Layers Character/Graphic LCD Controller
4. Pin Definition
4-1 MPU Interface
Pin Name
I/O
Description
Data Bus
These are data bus for data transfer between MPU and RA8806.
The high nibble DATA[7:4] is output and should keep floating when 4-bits
data bus mode is used.
I/O
DATA[7:0]
Enable/Read Enable
ZRD
(EN)
When MPU interface(I/F) is 8080 series, this pin (ZRD) is used as data
read, active low.
When MPU I/F is 6800 series, this pin (EN) is used as Enable, active high.
I
I
Write/Read-Write
When MPU I/F is 8080 series, this pin (ZWR) is used as data write, active
low.
When MPU I/F is 6800 series, this pin(ZRW) is used as data read/write
control. Active high for read and active low for write.
ZWR
(ZRW)
Command / Data Select Input
The pin is used to select command/data cycle. RS = 0, data Read/Write
cycle is selected. RS = 1, status read/command write cycle is selected.
In 8080 interface, usually it connects to “A0” address pin.
RS
0
ZWR
Access Cycle
Data Write
I
RS
0
1
0
1
0
1
1
Data Read
CMD Write
Status Read
Chip Select Input
ZCS1
CS2
The MPU interface of RA8806 is active only when ZCS1 is low and CS2 is
high.
I
Interrupt Signal Output
The interrupt output for MPU to indicate the status of RA8806. It could be
setup active high or low.
O
INT
Busy Signal Output
This is a busy output to indicate the RA8806 is in busy state. It could be
set to active high or active low by register. The RA8806 can’t access MPU
cycle when BUSY pin is active.
O
BUSY
It could be used for MPU to poll busy status by connecting it to I/O port.
4-2 Clock Interface
Pin Name
XG
I/O
Description
X’tal Input
In internal clock mode, this pin connects to external X’tal(4M ~ 12MHz).
In external clock mode, it connects to external clock.
I
X’tal Output
This pin connects to external X’tal(4M ~ 12MHz). In external clock mode, it
keeps floating.
O
XD
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