ST7FL15F1MAE STMICROELECTRONICS [STMicroelectronics], ST7FL15F1MAE Datasheet - Page 44

• Manufacturer Part Number: ST7FL15F1MAE
• Description: 8-bit MCU for automotive with single voltage Flash/ROM memory, data EEPROM, ADC, 5 timers, SPI
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ST7L15, ST7L19
I/O PORTS (cont’d)
10.2.2 Output Modes
Setting the DDRx bit selects output mode. Writing
to the DR bits applies a digital value to the I/O
through the latch. Reading the DR bits returns the
previously stored value.
If an OR bit is available, different output modes
can be selected by software: Push-pull or open-
drain. Refer to
page 47
DR Value and Output Pin Status
44/138
1
– Set the interrupt mask with the SIM instruction
– Select falling edge
– Disable the external interrupt through the OR
– Select rising edge
– Reset the interrupt mask with the RIM instruc-
SIM (in cases where a pin level change could
occur)
register
tion (in cases where a pin level change could
occur)
DR
0
1
for configuration.
“I/O PORT IMPLEMENTATION” on
Push-Pull
V
V
OH
OL
Open-Drain
Floating
V
OL
10.2.3 Alternate Functions
Many ST7 I/Os have one or more alternate func-
tions. These may include output signals from, or
input signals to, on-chip peripherals. The Device
Pin Description table describes which peripheral
signals can be input/output to which ports.
A signal coming from an on-chip peripheral can be
output on an I/O. To do this, enable the on-chip
peripheral as an output (enable bit in the peripher-
al’s control register). The peripheral configures the
I/O as an output and takes priority over standard I/
O programming. The I/O’s state is readable by ad-
dressing the corresponding I/O data register.
Configuring an I/O as floating enables alternate
function input. It is not recommended to configure
an I/O as pull-up as this increases current con-
sumption. Before using an I/O as an alternate in-
put, configure it without interrupt. Otherwise spuri-
ous interrupts can occur.
Configure an I/O as input floating for an on-chip
peripheral signal which can be input and output.
Caution: I/Os which can be configured as both an
analog and digital alternate function need special
attention. The user must control the peripherals so
that the signals do not arrive at the same time on
the same pin. If an external clock is used, only the
clock alternate function should be employed on
that I/O pin and not the other alternate function.