DS89C420_02 Datasheet, PDF (53/58 Pages) Maxim Integrated Products – Ultra-High-Speed Microcontroller

Figure 14. SERIAL PORT TIMING
SERIAL PORT (SYNCHRONOUS MODE)
SM2 = 1 TDX CLOCK = XTAL FREQ/4
ALE
PSEN
WRITE TO SBUF
RXD DATA OUT
tQVXH
tXHQX
D0
DI
D2
D3
D4
D5
D6
D7
TXD CLOCK
TI
tXLXL
WRITE TO SCON
TO CLEAR RI
RXD DATA IN
TXD CLOCK
R1
D0
DI
D2
D3
D4
D5
D6
D7
tXHDV
tXHDX
DS89C420
TRANSMIT
RECEIVE
SERIAL PORT (SYNCHRONOUS MODE)
SM2 = 0 TDX CLOCK = XTAL FREQ/12
ALE
PSEN
WRITE TO SBUF
RXD DATA OUT
TXD CLOCK
TI
WTRXIDTECLTOOCSKCON
TO CLEAR RI
RXD DATA IN
TXD CLOCK
R1
1/(XTAL FREQ/12)
D0
DI
D6
D7
D0
DI
D6
D7
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