13

CPU Interface

1. Function of the RDY (Ready) pin

The built-in RAM is a single-port RAM. To prevent contention between the access from the CPU side and the

reading by the liquid-crystal drive side, the RDY pin performs a Wait operation on the CPU.

•••• Timing

Wait

Ready

A0 - A16, /UBE

/CS

/OE, /WE

RDY

Hi-Z

Hi-Z

Wait

•••• Connection of the RDY pin

The RDY pin uses a three-state buffer. The RDY pin should be connected to an external pull-up resister. If more

than one LSI are used, the RDY pins of each LSI are wired together.

CPU

Ready input

RDY

Column driver

RDY

Column driver

Pull-up resister

•