HD64570 Datasheet, PDF (123/469 Pages) Hitachi Semiconductor – Serial Communications Adaptor

TXC
TXD
RTS
Write 1 to RTS bit
(a) Auto-Enable, 5 Bits/Character, No Parity, and 1/1 Clock Mode
MPU write cycle
T1
T2
T3
T4
CLK
WR
RTS
(b) CPU Mode 0, MPU Write Cycle
Figure 5.1 Modem Control Signal Timing
Rev. 0, 07/98, page 107 of 453