µPD31172
(c) Serial transmission timing
RXD
(input)
Start bit
DATA (5:8)
Parity bit Stop bit Start bit
t
IRS
t
STI
INTRPNote
t
HR
(output)
t
SI
t
HR
IOW# (input)
(writing to THR
register)
t
IR
IOR# (input)
(reading IIR
register)
Note Dependant on whether the transmit buffer is empty. At this time, bit 1 of the IER register is 1, and bits 3
to 1 of the IIR register are 0, 0, 1, respectively.
(d) Serial modem control timing
IOW# (input)
(writing to MCR
register)
t
MDO
t
MDO
RTS#, DTR#
(output)
CTS#, DSR#,
DCD# (input)
t
SIM
t
SIM
INTRPNote
(output)
t
RIM
t
RIM
IOR# (input)
(reading MSR
register)
t
SIM
RI# (input)
Note Dependant on the modem status. At this time, bit 3 of the IER register is 1, and bits 3 to 1 of the IIR
register are 0, 0, 0, respectively.
29
Data Sheet U14388EJ2V0DS00
NEC [ NEC ]
