CD00001237 Datasheet, PDF (39/105 Pages) STMicroelectronics – 8-bit MCUs with A/D converter

I/O PORTS (Cont’d)
Figure 23. I/O Port Block Diagram
RESET
DATA
DIRECTION
REGISTER
ST6
INTERNAL
BUS
DATA
REGISTER
OPTION
REGISTER
ST6215C ST6225C
PULL-UP
V_DD
V_DD
V_DD
Pxx I/O Pin
N-BUFFER
P-BUFFER
CLAMPING
DIODES
TO INTERRUPT
TO ADC
CMOS
SCHMITT
TRIGGER
Table 8. I/O Port Configurations
DDR
OR
0
0
0
0
0
1
0
1
1
0
1
1
DR
Mode
0
Input
1
Input
0
Input
1
Input
x
Output
x
Output
Note: x = Don’t care
Option
With pull-up, no interrupt
No pull-up, no interrupt
With pull-up and with interrupt
Analog input (when available)
Open-drain output (20mA sink when available)
Push-pull output (20mA sink when available)
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