ST72101 Datasheet, PDF (26/84 Pages) STMicroelectronics – 8-BIT MCU WITH 4 TO 8K ROM/OTP/EPROM, 256 BYTES RAM, ADC, WDG, SPI AND 1 OR 2 TIMERS

ST72101/ST72212/ST72213
I/O PORTS (Cont’d)
Figure 20. I/O Block Diagram
ALTERNATE ENABLE
ALTERNATE ¹
OUTPUT
M
U
X
0
V_DD
P-BUFFER
(SEE TABLE BELOW)
DR
LATCH
DDR
LATCH
ALTERNATE
ENABLE
PULL-UP
CONDITIO N
PULL-UP
V_DD
DIODE
(SEE TABLE BELOW)
OR
LATCH
(SEE TABLE BELOW)
ANALOG ENABLE
(ADC)
PAD
OR SEL
DDR SEL
ANALOG
S WITC H
(SEE NOTE BELOW)
GND
DR SEL
ALTERNATE INPUT
1
M
U
X
0
ALTERNATE
ENABLE
N-BUFFER
GND
EXTERNAL
INTERRUPT
SOURCE (EIx)
POLARITY
SEL
FROM
OTHER
BITS
Table 10. Port Mode Configuration
Configu ration Mode
Floating
Pull-up
Push-pull
True Open Drain
Open Drain (logic level)
Legend:
0 - present, not activated
1 - present and activated
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CMOS
SCHMITT TRIGGER
Pull-up
0
1
0
not present
0
P-buff er
0
0
1
not present
0
V_DD Diode
1
1
1
not present in OTP
and EPROM devices
1
Notes:
– No OR Register on some ports (see register map).
– ADC Switch on ports with analog alternate functions.