Drivers for Raspberry Pi Peripherals. More...

Files
file	gpio.c
	Implementation of functions for manipulating GPIO registers.

file	led.c
	Implementation of functions for manipulating a LED to a GPIO pin.

file	mmio.c
	Implementation of MMIO functions.

file	timer.c
	Implementation of basic System Timer functions.

file	uart.c
	Implementation of basic UART functions.

file	gpio.h
	Definition of functions for manipulating GPIO registers.

file	led.h
	Definition of functions for manipulating a LED to a GPIO pin.

file	mmio.h
	Definition of MMIO functions.

file	timer.h
	Definition of basic System Timer functions.

file	uart.h
	Definition of basic UART functions.

Macros
#define	LED_PIN 17

#define	LED_MSEC_IRQ 200

#define	MAX_INPUT_LENGTH 80

Functions
int	gpio_pin_set_func (uint8_t pin_num, gpio_func func)

int	gpio_pin_set (uint8_t pin_num)

int	gpio_pin_clear (uint8_t pin_num)

int	led_init (uint8_t pin_num)

void	led_on (uint8_t pin_num)

void	led_off (uint8_t pin_num)

void	led_on_ms (uint8_t pin_num, uint32_t msec)

void	led_pulse (uint8_t pin_num, uint32_t msec)

void	led_blink_times (uint8_t pin_num, size_t count, uint32_t msec)

void	led_blink_sos (uint8_t pin_num, uint32_t msec)

void	mmio_write (uint64_t reg, uint32_t data)

uint32_t	mmio_read (uint64_t reg)

void	delay (int32_t count)

void	timer_1_init (uint32_t msec)

void	timer_3_init (uint32_t msec)

void	timer_1_stop ()

void	timer_3_stop ()

uint64_t	timer_get_ticks ()

void	timer_msleep (uint32_t msec)

void	uart_init ()

void	uart_putc (unsigned char c)

unsigned char	uart_getc ()

void	uart_puts (const char *str)

char *	uart_gets ()

Detailed Description

Drivers for Raspberry Pi Peripherals.

Macro Definition Documentation

◆ LED_MSEC_IRQ

#define LED_MSEC_IRQ 200

The pulse time in milliseconds for the LED IRQ.

◆ LED_PIN

#define LED_PIN 17

Raspi 3, 4 -> GPIO 17 (LED Connected on physical pin 11)

Warning: This should change according to the pin you have the LED connected.

◆ MAX_INPUT_LENGTH

#define MAX_INPUT_LENGTH 80

Maximum length for the serial input.

Warning: It is a temporary solution, because of no support for dynamic allocation of memory.

See also: console(), uart_gets(), process.c

Function Documentation

◆ delay()

void delay ( int32_t count )

Delays count of clock cycles.

Parameters

count Number of cycles.

◆ gpio_pin_clear()

int gpio_pin_clear ( uint8_t pin_num )

Clears the GPIO pin (Low) at pin_num, using GPCLRn ( GPCLR0, GPCLR1).

Parameters

pin_num GPIO pin number.

Returns

On success: 0
On failure: -1

See also: peripherals/gpio.h

◆ gpio_pin_set()

int gpio_pin_set ( uint8_t pin_num )

Sets the GPIO pin (High) at pin_num, using GPSETn ( GPSET0, GPSET1).

Parameters

pin_num GPIO pin number.

Returns

On success: 0
On failure: -1

See also: peripherals/gpio.h

◆ gpio_pin_set_func()

int gpio_pin_set_func	(	uint8_t	pin_num,
		gpio_func	func
	)

Sets the Alternative Function func for GPIO pin at pin_num, using GPFSELn ( GPFSEL0 - GPFSEL5).

Parameters

pin_num	GPIO pin number.
func	Alternative Function.

Returns

On success: 0
On failure: -1

See also: gpio_func, peripherals/gpio.h

◆ led_blink_sos()

void led_blink_sos	(	uint8_t	pin_num,
		uint32_t	msec
	)

Makes LED at pin_num, to blink an SOS message, with an msec interval (in milliseconds).

Parameters

pin_num	GPIO pin number.
msec	Time to sleep in milliseconds.

See also: led_on(), led_off(), timer_msleep()

◆ led_blink_times()

void led_blink_times	(	uint8_t	pin_num,
		size_t	count,
		uint32_t	msec
	)

Makes LED at pin_num, to blink count times, for msec milliseconds.

Parameters

pin_num	GPIO pin number.
count	Number of times to blink.
msec	Time to sleep in milliseconds.

See also: led_pulse()

Example

led_blink_times(LED_PIN, 10, 500);

◆ led_init()

int led_init ( uint8_t pin_num )

Sets pin_num GPIO pin as Output.

Parameters

pin_num GPIO pin number.

Returns

On success: 0
On failure: -1

See also: gpio_pin_set_func()

◆ led_off()

void led_off ( uint8_t pin_num )

Turns LED at pin_num OFF.

Parameters

pin_num GPIO pin number.

See also: gpio_pin_clear()

◆ led_on()

void led_on ( uint8_t pin_num )

Turns LED at pin_num ON.

Parameters

pin_num GPIO pin number.

See also: gpio_pin_set()

◆ led_on_ms()

void led_on_ms	(	uint8_t	pin_num,
		uint32_t	msec
	)

Turns LED at pin_num ON for msec milliseconds.

Parameters

pin_num	GPIO pin number.
msec	Time to sleep in milliseconds.

See also: led_on(), led_off(), timer_msleep()

◆ led_pulse()

void led_pulse	(	uint8_t	pin_num,
		uint32_t	msec
	)

Makes LED at pin_num, to blink once for msec milliseconds.

Parameters

pin_num	GPIO pin number.
msec	Time to sleep in milliseconds.

See also: led_on(), led_off(), timer_msleep()

◆ mmio_read()

uint32_t mmio_read ( uint64_t reg )

Memory-Mapped I/O input.

Parameters

reg	64-bit register address.

Returns: 32-bit data.

Reads register at reg address and returns its data.

◆ mmio_write()

void mmio_write	(	uint64_t	reg,
		uint32_t	data
	)

Memory-Mapped I/O output.

Parameters

reg	64-bit register address.
data	32-bit data.

Writes the data value to the register at reg address.

◆ timer_1_init()

void timer_1_init ( uint32_t msec )

Initializes System Timer 1, with a time interval of msec milliseconds.

Parameters

msec	Time interval in milliseconds.

Initialization steps:

Sets time interval to be msec milliseconds.
Reads current counter value from TIMER_CLO.
Increases it by an interval ( interval_1).
Sets this value to be compared for System Timer 1 Interrupt.

See also: peripherals/timer.h

◆ timer_1_stop()

void timer_1_stop ( )

Disables System Timer 1.

Set 0 to compare register TIMER_C1, in order to stop timer interrupts.

See also: peripherals/timer.h

◆ timer_3_init()

void timer_3_init ( uint32_t msec )

Initializes System Timer 3, with a time interval of msec milliseconds.

Parameters

msec	Time interval in milliseconds.

Initialization steps:

Sets time interval to be msec milliseconds.
Reads current counter value from TIMER_CLO.
Increases it by an interval ( interval_3).
Sets this value to be compared for System Timer 3 Interrupt.

See also: peripherals/timer.h

◆ timer_3_stop()

void timer_3_stop ( )

Disables System Timer 3.

Set 0 to compare register TIMER_C3, in order to stop timer interrupts.

See also: peripherals/timer.h

◆ timer_get_ticks()

uint64_t timer_get_ticks ( )

Reads the 64-bit free running counter value that contains, the number of ticks since the system's initialization.

Returns: Number of ticks.

Reads the values from the TIMER_CHI and TIMER_CLO registers, and creates the full 64-bit counter value by left shifting the 32 high bits.

See also: peripherals/timer.h

◆ timer_msleep()

void timer_msleep ( uint32_t msec )

Sleeps for msec milliseconds, using the timers free running counter.

Parameters

msec	Time interval in milliseconds.

Get counters current calue from timer_get_ticks() and waits until msec have passed from start.

Note: Blocking function.

See also: timer_get_ticks()

◆ uart_getc()

unsigned char uart_getc ( )

Gets a byte to the UART (serial input).

Returns: The byte received from the UART.

First waits for the UART to have received something, and then reads the contents of the AUX_MU_IO_REG register

See also: peripherals/aux.h

◆ uart_gets()

char* uart_gets ( )

Gets a string from the UART (serial input).

Returns: A pointer to a static char array, that the string is saved.

Reads in a loop a byte from the serial input using the uart_getc() function until a New Line (\n) or a Carriage Return (\r) char is received. Echoes back each char to the serial output.

Note: Gets up to MAX_INPUT_LENGTH chars.; Always appends a null terminator (\0) at the end of the string.

See also: uart_getc(), MAX_INPUT_LENGTH

◆ uart_init()

void uart_init ( )

Initializes the UART interface based on the running device.

Basic configuration:

Sets Alternative Function 5 for GPIO pins 14, 15, in order to enable mini UART.
Disables pull up/down resistors for pins 14, 15.
Enables mini UART.
Disables auto flow control and disables receiver and transmitter.
Enables receive and transmit interrupts.
Clears the receive and transmit FIFO, and enables FIFO.
Enables 8 bit mode.
Sets RTS line to be always high.
Sets baud rate at 115200.
Enables transmitter and receiver.

See also: peripherals/gpio.h, peripherals/aux.h

◆ uart_putc()

void uart_putc ( unsigned char c )

Sends a byte to the UART (serial output).

Parameters

c	The byte sent to the UART.

First waits for the UART to become ready to transmit, and then writes the byte c to the AUX_MU_IO_REG register.

See also: peripherals/aux.h

◆ uart_puts()

void uart_puts ( const char * str )

Sends a string to the UART (serial output).

Parameters

str	A string pointer for the string to send to the UART.

Iterates over the string and prints each char to the serial output.

Note: If a new New Line (\n) char is found, it appends a Carriage Return (\r) char, so there is no need to include the \r char in the str string.

See also: uart_putc()

Files

Macros

Functions

Detailed Description

Macro Definition Documentation

◆ LED_MSEC_IRQ

◆ LED_PIN

◆ MAX_INPUT_LENGTH

Function Documentation

◆ delay()

◆ gpio_pin_clear()

◆ gpio_pin_set()

◆ gpio_pin_set_func()

◆ led_blink_sos()

◆ led_blink_times()

Example

◆ led_init()

◆ led_off()

◆ led_on()

◆ led_on_ms()

◆ led_pulse()

◆ mmio_read()

◆ mmio_write()

◆ timer_1_init()

◆ timer_1_stop()

◆ timer_3_init()

◆ timer_3_stop()

◆ timer_get_ticks()

◆ timer_msleep()

◆ uart_getc()

◆ uart_gets()

◆ uart_init()

◆ uart_putc()

◆ uart_puts()