ST72321J9-Auto STMicroelectronics, ST72321J9-Auto Datasheet - Page 74

• Manufacturer Part Number: ST72321J9-Auto
• Description: 8-bit MCU for automotive with 60 Kbyte Flash, 10-bit ADC, timers, SPI, SCI and I2C interfaces
• Manufacturer: STMicroelectronics

Specifications of ST72321J9-Auto

• Hdflash Endurance: 100 cycles, data retention 20 years
• Clock Sources: crystal/ceramic resonator oscillators, internal RC oscillator and bypass for external clock
• 4 Power Saving Modes: Halt, Active Halt, Wait and Slow

I/O ports
Caution:
9.3
74/243
The alternate function must not be activated 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 selected pin to the common analog rail which is connected 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 analog pin.
I/O port implementation
The hardware implementation on each I/O port depends on the settings in the DDR and OR
registers and specific feature of the I/O port such as ADC Input or true open-drain.
Switching these I/O ports from one state to another should be done in a sequence that
prevents unwanted side effects. Recommended safe transitions are illustrated in
Other transitions are potentially risky and should be avoided, since they are likely to present
unwanted side-effects such as spurious interrupt generation.
Figure 30. Interrupt I/O port state transitions
The I/O port register configurations are summarized in the following table.
Table 31.
Port A
Port
Warning:
PA7:6
PA5:4
PA3
PA2:0
Pin name
I/O port configuration
floating/pull-up
The analog input voltage level must be within the limits
stated in the absolute maximum ratings.
interrupt
INPUT
01
Doc ID 13829 Rev 1
OR = 0
floating
floating
floating
(reset state)
Input (DDR = 0)
floating
INPUT
00
floating
floating interrupt
pull-up interrupt
OR = 1
pull-up
open-drain
OUTPUT
10
XX
= DDR, OR
open-drain
open-drain
open-drain
OR = 0
OUTPUT
push-pull
Output (DDR = 1)
11
true open-drain
ST72321xx-Auto
push-pull
push-pull
push-pull
OR = 1
Figure 30.