DS89C420_05 Datasheet, PDF (10/47 Pages) Maxim Integrated Products – Ultra-High-Speed Microcontroller

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