ST72254G2-Auto STMicroelectronics, ST72254G2-Auto Datasheet - Page 33

• Manufacturer Part Number: ST72254G2-Auto
• Description: 8-bit MCU for automotive with single voltage Flash/ROM memory, ADC, 16-bit timers, SPI, I2C interfaces
• Manufacturer: STMicroelectronics

Specifications of ST72254G2-Auto

• Clock Sources: crystal/ceramic resonator oscillators or RC oscillators, external clock, backup Clock Security System
• 3 Power Saving Modes: Halt, Wait and Slow
• Two 16-bit Timers With: 2 input captures, 2 output compares, external clock input on one timer, PWM and Pulse generator modes (one only on ST72104Gx-Auto and ST72216G1- Auto)

I/O PORTS (Cont’d)
Caution: The alternate function must not be acti-
vated as long as the pin is configured as input with
interrupt, in order to avoid generating spurious in-
terrupts.
Analog alternate function
When the pin is used as an ADC input, the I/O
must be configured as floating input. The analog
multiplexer (controlled by the ADC registers)
switches the analog voltage present on the select-
ed pin to the common analog rail which is connect-
ed to the ADC input.
It is recommended not to change the voltage level
or loading on any port pin while conversion is in
progress. Furthermore it is recommended not to
have clocking pins located close to a selected an-
alog pin.
Warning: The analog input voltage level must be
within the limits stated in the absolute maximum
ratings.
9.3 I/O PORT IMPLEMENTATION
The hardware implementation on each I/O port de-
pends on the settings in the DDR and OR registers
and specific feature of the I/O port such as ADC In-
put or true open drain.
Switching these I/O ports from one state to anoth-
er should be done in a sequence that prevents un-
wanted side effects. Recommended safe transi-
tions are illustrated in
are potentially risky and should be avoided, since
they are likely to present unwanted side-effects
such as spurious interrupt generation.
Table 8. Port Configuration
Port A
Port B
Port C
Port
Pin name
PA3:0
PB7:0
PC7:0
PA7
PA6
PA5
PA4
ST72104Gx-Auto, ST72215Gx-Auto, ST72216Gx-Auto, ST72254Gx-Auto
Figure 21.
OR = 0
floating
floating
floating
floating
floating
floating
floating
Input (DDR = 0)
Other transitions
floating interrupt
floating interrupt
pull-up interrupt
pull-up interrupt
pull-up interrupt
pull-up interrupt
pull-up interrupt
OR = 1
Figure 21. Interrupt I/O Port State Transitions
The I/O port register configurations are summa-
rized as follows.
Interrupt Ports
PA7, PA5, PA3:0, PB7:0, PC5:0 (with pull-up)
True Open Drain Interrupt Ports
PA6, PA4 (without pull-up)
floating input
pull-up interrupt input
open drain output
push-pull output
floating input
floating interrupt input
open drain (high sink ports)
floating/pull-up
interrupt
INPUT
open drain
open drain
open drain
open drain
open drain
OR = 0
01
true open-drain
true open-drain
MODE
MODE
(reset state)
floating
INPUT
Output (DDR = 1)
00
push-pull
push-pull
push-pull
push-pull
push-pull
OR = 1
open-drain
OUTPUT
10
XX = DDR, OR
DDR
DDR
0
0
1
1
0
0
1
High-Sink
Yes
No
OUTPUT
push-pull
11
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OR
OR
X
0
1
0
1
0
1