This driver for Atmel® | SMART ARM®-based microcontrollers provides an interface for the configuration and management of the device's physical I/O Pins, to alter the direction and input/drive characteristics as well as to configure the pin peripheral multiplexer selection.
The following peripheral is used by this module:
The following devices can use this module:
The outline of this documentation is as follows:
There are no prerequisites for this module.
The SAM devices contain a number of General Purpose I/O pins, used to interface the user application logic and internal hardware peripherals to an external system. The Pin Multiplexer (PINMUX) driver provides a method of configuring the individual pin peripheral multiplexers to select alternate pin functions.
| Driver Feature Macro | Supported devices |
|---|---|
| FEATURE_SYSTEM_PINMUX_DRIVE_STRENGTH | SAM L21, SAM C20/C21, SAM R34/R35 |
SAM devices use two naming conventions for the I/O pins in the device; one physical and one logical. Each physical pin on a device package is assigned both a physical port and pin identifier (e.g. "PORTA.0") as well as a monotonically incrementing logical GPIO number (e.g. "GPIO0"). While the former is used to map physical pins to their physical internal device module counterparts, for simplicity the design of this driver uses the logical GPIO numbers instead.
SAM devices contain a peripheral MUX, which is individually controllable for each I/O pin of the device. The peripheral MUX allows you to select the function of a physical package pin - whether it will be controlled as a user controllable GPIO pin, or whether it will be connected internally to one of several peripheral modules (such as an I2C module). When a pin is configured in GPIO mode, other peripherals connected to the same pin will be disabled.
There are several special modes that can be selected on one or more I/O pins of the device, which alter the input and output characteristics of the pad.
The Drive Strength configures the strength of the output driver on the pad. Normally, there is a fixed current limit that each I/O pin can safely drive, however some I/O pads offer a higher drive mode which increases this limit for that I/O pin at the expense of an increased power consumption.
The Slew Rate configures the slew rate of the output driver, limiting the rate at which the pad output voltage can change with time.
The Input Sample Mode configures the input sampler buffer of the pad. By default, the input buffer is only sampled "on-demand", i.e. when the user application attempts to read from the input buffer. This mode is the most power efficient, but increases the latency of the input sample by two clock cycles of the port clock. To reduce latency, the input sampler can instead be configured to always sample the input buffer on each port clock cycle, at the expense of an increased power consumption.
The diagram below shows how this module is interconnected within the device:
The SAM port pin input sampling mode is set in groups of four physical pins; setting the sampling mode of any pin in a sub-group of eight I/O pins will configure the sampling mode of the entire sub-group.
High Drive Strength output driver mode is not available on all device pins - refer to your device specific datasheet.
For extra information, see Extra Information for SYSTEM PINMUX Driver. This includes:
For a list of examples related to this driver, see Examples for SYSTEM PINMUX Driver.
Data Structures | |
| struct | system_pinmux_config |
| Port pin configuration structure. More... | |
Macros | |
| #define | SYSTEM_PINMUX_GPIO (1 << 7) |
| Peripheral multiplexer index to select GPIO mode for a pin. More... | |
Enumerations | |
| enum | system_pinmux_pin_dir { SYSTEM_PINMUX_PIN_DIR_INPUT, SYSTEM_PINMUX_PIN_DIR_OUTPUT, SYSTEM_PINMUX_PIN_DIR_OUTPUT_WITH_READBACK } |
| Port pin direction configuration enum. More... | |
| enum | system_pinmux_pin_pull { SYSTEM_PINMUX_PIN_PULL_NONE, SYSTEM_PINMUX_PIN_PULL_UP, SYSTEM_PINMUX_PIN_PULL_DOWN } |
| Port pin input pull configuration enum. More... | |
| enum | system_pinmux_pin_sample { SYSTEM_PINMUX_PIN_SAMPLE_CONTINUOUS, SYSTEM_PINMUX_PIN_SAMPLE_ONDEMAND } |
| Port pin digital input sampling mode enum. More... | |
Configuration and Initialization | |
| static void | system_pinmux_get_config_defaults (struct system_pinmux_config *const config) |
| Initializes a Port pin configuration structure to defaults. More... | |
| void | system_pinmux_pin_set_config (const uint8_t gpio_pin, const struct system_pinmux_config *const config) |
| Writes a Port pin configuration to the hardware module. More... | |
| void | system_pinmux_group_set_config (PortGroup *const port, const uint32_t mask, const struct system_pinmux_config *const config) |
| Writes a Port pin group configuration to the hardware module. More... | |
Special Mode Configuration (Physical Group Orientated) | |
| static PortGroup * | system_pinmux_get_group_from_gpio_pin (const uint8_t gpio_pin) |
| Retrieves the PORT module group instance from a given GPIO pin number. More... | |
| void | system_pinmux_group_set_input_sample_mode (PortGroup *const port, const uint32_t mask, const enum system_pinmux_pin_sample mode) |
| Configures the input sampling mode for a group of pins. More... | |
Special Mode Configuration (Logical Pin Orientated) | |
| static uint8_t | system_pinmux_pin_get_mux_position (const uint8_t gpio_pin) |
| Retrieves the currently selected MUX position of a logical pin. More... | |
| static void | system_pinmux_pin_set_input_sample_mode (const uint8_t gpio_pin, const enum system_pinmux_pin_sample mode) |
| Configures the input sampling mode for a GPIO pin. More... | |
| #define SYSTEM_PINMUX_GPIO (1 << 7) |
Peripheral multiplexer index to select GPIO mode for a pin.
Referenced by _system_pinmux_config(), port_group_set_config(), port_pin_set_config(), system_pinmux_get_config_defaults(), and system_pinmux_pin_get_mux_position().
Port pin direction configuration enum.
Enum for the possible pin direction settings of the port pin configuration structure, to indicate the direction the pin should use.
Port pin input pull configuration enum.
Enum for the possible pin pull settings of the port pin configuration structure, to indicate the type of logic level pull the pin should use.
Port pin digital input sampling mode enum.
Enum for the possible input sampling modes for the port pin configuration structure, to indicate the type of sampling a port pin should use.
|
inlinestatic |
Initializes a Port pin configuration structure to defaults.
Initializes a given Port pin configuration structure to a set of known default values. This function should be called on all new instances of these configuration structures before being modified by the user application.
The default configuration is as follows:
| [out] | config | Configuration structure to initialize to default values |
References Assert, system_pinmux_config::direction, system_pinmux_config::input_pull, system_pinmux_config::mux_position, system_pinmux_config::powersave, SYSTEM_PINMUX_GPIO, SYSTEM_PINMUX_PIN_DIR_INPUT, and SYSTEM_PINMUX_PIN_PULL_UP.
Referenced by extint_chan_set_config(), extint_nmi_set_config(), port_group_set_config(), port_pin_set_config(), usart_init(), and usb_init().
|
inlinestatic |
Retrieves the PORT module group instance from a given GPIO pin number.
Retrieves the PORT module group instance associated with a given logical GPIO pin number.
| [in] | gpio_pin | Index of the GPIO pin to convert |
References Assert.
Referenced by port_get_group_from_gpio_pin(), system_pinmux_pin_get_mux_position(), system_pinmux_pin_set_config(), and system_pinmux_pin_set_input_sample_mode().
| void system_pinmux_group_set_config | ( | PortGroup *const | port, |
| const uint32_t | mask, | ||
| const struct system_pinmux_config *const | config | ||
| ) |
Writes a Port pin group configuration to the hardware module.
Writes out a given configuration of a Port pin group configuration to the hardware module.
| [in] | port | Base of the PORT module to configure |
| [in] | mask | Mask of the port pin(s) to configure |
| [in] | config | Configuration settings for the pin |
References _system_pinmux_config(), and Assert.
Referenced by port_group_set_config().
| void system_pinmux_group_set_input_sample_mode | ( | PortGroup *const | port, |
| const uint32_t | mask, | ||
| const enum system_pinmux_pin_sample | mode | ||
| ) |
Configures the input sampling mode for a group of pins.
Configures the input sampling mode for a group of pins, to control when the physical I/O pin value is sampled and stored inside the microcontroller.
| [in] | port | Base of the PORT module to configure |
| [in] | mask | Mask of the port pin(s) to configure |
| [in] | mode | New pin sampling mode to configure |
References Assert, and SYSTEM_PINMUX_PIN_SAMPLE_ONDEMAND.
|
inlinestatic |
Retrieves the currently selected MUX position of a logical pin.
Retrieves the selected MUX peripheral on a given logical GPIO pin.
| [in] | gpio_pin | Index of the GPIO pin to configure |
References system_pinmux_get_group_from_gpio_pin(), and SYSTEM_PINMUX_GPIO.
| void system_pinmux_pin_set_config | ( | const uint8_t | gpio_pin, |
| const struct system_pinmux_config *const | config | ||
| ) |
Writes a Port pin configuration to the hardware module.
Writes out a given configuration of a Port pin configuration to the hardware module.
| [in] | gpio_pin | Index of the GPIO pin to configure |
| [in] | config | Configuration settings for the pin |
References _system_pinmux_config(), and system_pinmux_get_group_from_gpio_pin().
Referenced by extint_chan_set_config(), extint_nmi_set_config(), port_pin_set_config(), usart_init(), and usb_init().
|
inlinestatic |
Configures the input sampling mode for a GPIO pin.
Configures the input sampling mode for a GPIO input, to control when the physical I/O pin value is sampled and stored inside the microcontroller.
| [in] | gpio_pin | Index of the GPIO pin to configure |
| [in] | mode | New pin sampling mode to configure |
References system_pinmux_get_group_from_gpio_pin(), and SYSTEM_PINMUX_PIN_SAMPLE_ONDEMAND.
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