Texas Instruments Tiva TM4C123GH6PM, Руководство пользователя

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GPIO
10 GPIO
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
10.1 Introduction
The GPIO module provides control for up to eight independent GPIO pins (the actual number
present depend upon the GPIO port and part number). Each pin has the following capabilities:
Can be configured as an input or an output. On reset, they default to being an input.
In input mode, can generate interrupts on high level, low level, rising edge, falling edge, or
both edges.
In output mode, can be configured for 2 mA, 4 mA, or 8 mA drive strength. The 8 mA drive
strength configuration has optional slew rate control to limit the rise and fall times of the signal.
On reset, they default to 2 mA drive strength.
Optional weak pull-up or pull-down resistors. On reset, they default to no pull-up or pull-down
resistors.
Optional open-drain operation. On reset, they default to standard push/pull operation.
Can be configured to be a GPIO or a peripheral pin. On reset, they default to being GPIOs.
Note that not all pins on all parts have peripheral functions, in which case the pin is only useful
as a GPIO (that is, when configured for peripheral function the pin will not do anything useful).
Most of the GPIO functions can operate on more than one GPIO pin (within a single module) at a
time. The
ui8Pins parameter to these functions is used to specify the pins that are affected; the
GPIO pins whose corresponding bits in this parameter that are set will be affected (where pin 0 is
in bit 0, pin 1 in bit 1, and so on). For example, if
ui8Pins is 0x09, then pins 0 and 3 will be affected
by the function.
This is most useful for the ROM_GPIOPinRead() and ROM_GPIOPinWrite() functions; a read will
return only the value of the requested pins (with the other pin values masked out) and a write will
affect the requested pins simultaneously (that is, the state of multiple GPIO pins can be changed
at the same time). This data masking for the GPIO pin state occurs in the hardware; a single read
or write is issued to the hardware, which interprets some of the address bits as an indication of the
GPIO pins to operate upon (and therefore the ones to not affect). See the part data sheet for details
of the GPIO data register address-based bit masking.
For functions that have a ui8Pin (singular) parameter, only a single pin is affected by the function.
In this case, this value specifies the pin number (that is, 0 through 7).
10.2 Functions
Functions
void ROM_GPIOADCTriggerDisable (uint32_t ui32Port, uint8_t ui8Pins)
void ROM_GPIOADCTriggerEnable (uint32_t ui32Port, uint8_t ui8Pins)
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