UPD16664 Datasheet, PDF (25/52 Pages) NEC – 144/160/184/208-OUTPUT LCD COLUMN SEGMENT DRIVER WITH RAM

µ PD16664
12. CPU INTERFACE
12.1 Function of RDY(ready) Pin
The internal RAM is a single-port RAM. The CPU is kept waiting so that access from the CPU does not conflict with
reading by the driver.
(1) Timing
A0 to A16,/UBE
/CS
/OE,/WE
Hi-Z
RDY
Hi-Z
Wait
Ready
Wait
(2) Connection of RDY pin
The RDY pin uses a three-state buffer. The RDY pin should be connected to an external pull-up resistor. If more
than one LSI are used, the RDY pins of each LSI are wired together.
VCC2
CPU
Ready input
Pull-up resistor
RDY Column driver
RDY Column driver
Data Sheet S13780EJ1V0DS00
25