ST72C334J4TAE STMicroelectronics, ST72C334J4TAE Datasheet - Page 43

• Manufacturer Part Number: ST72C334J4TAE
• Description: 8-bit MCU for automotive with single voltage Flash/ROM memory, ADC, 16-bit timers, SPI, SCI interfaces
• Manufacturer: STMicroelectronics

I/O PORTS (Cont’d)
CAUTION: The alternate function must not be ac-
tivated as long as the pin is configured as input
with interrupt, in order to avoid generating spurious
interrupts.
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 maxi-
mum ratings.
11.3 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.
Figure 26. Interrupt I/O Port State Transitions
The I/O port register configurations are summa-
rized as follows.
floating/pull-up
interrupt
INPUT
01
(reset state)
floating
INPUT
00
Figure 26.
open-drain
OUTPUT
10
XX = DDR, OR
Other transitions
OUTPUT
push-pull
ST72334xx-Auto, ST72314xx-Auto, ST72124Jx-Auto
11
Standard Ports
PA5:4, PC7:0, PD7:0, PE7:4, PE1:0, PF7:6, PF4
Interrupt Ports
PA2:0, PB7:5, PB2:0, PF1:0 (with pull-up)
PA3, PB4, PB3, PF2 (without pull-up)
True Open Drain Ports
PA7:6
floating input
pull-up input
open drain output
push-pull output
floating input
pull-up interrupt input
open drain output
push-pull output
floating input
floating interrupt input
open drain output
push-pull output
floating input
open drain (high sink ports)
MODE
MODE
MODE
MODE
DDR
DDR
DDR
0
0
1
1
0
0
1
1
0
0
1
1
DDR
43/150
OR
OR
OR
0
1
0
1
0
1
0
1
0
1
0
1
0
1