ST7232AK1 STMicroelectronics, ST7232AK1 Datasheet - Page 45

• Manufacturer Part Number: ST7232AK1
• Description: 8-BIT MCU WITH 8K FLASH/ROM, ADC, 4 TIMERS, SPI, SCI INTERFACE
• Manufacturer: STMicroelectronics

Specifications of ST7232AK1

• Hdflash Endurance: 100 cycles, data retention
• Clock Sources: crystal/ceramic resonator oscillators and bypass for external clock
• Four Power Saving Modes: Halt, Active-Halt, Wait and Slow
• Main Clock Controller With: Real time base, Beep and Clock-out capabilities
• Two 16-bit Timers With: 2 input captures, 2 output compares, PWM and pulse generator modes

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.
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.
Figure 28
Other transitions
Figure 28. Interrupt I/O Port State Transitions
9.4 LOW POWER MODES
9.5 INTERRUPTS
The external interrupt event generates an interrupt
if the corresponding configuration is selected with
DDR and OR registers and the interrupt mask in
the CC register is not active (RIM instruction).
floating/pull-up
WAIT
HALT
External interrupt on
selected external
event
Mode
Interrupt Event
interrupt
INPUT
01
No effect on I/O ports. External interrupts
cause the device to exit from WAIT mode.
No effect on I/O ports. External interrupts
cause the device to exit from HALT mode.
(reset state)
floating
INPUT
00
Event
Flag
-
Description
open-drain
Control
OUTPUT
Enable
DDRx
ORx
Bit
10
XX
= DDR, OR
from
Wait
Exit
Yes
ST7232A
OUTPUT
push-pull
11
45/157
from
Exit
Halt
Yes
1