periph_conf.h File Reference

Configuration of CPU peripherals for Adafruit Feather M0. More...

Detailed Description

Configuration of CPU peripherals for Adafruit Feather M0.

Author
Alexandre Abadie alexa.nosp@m.ndre.nosp@m..abad.nosp@m.ie@i.nosp@m.nria..nosp@m.fr

Definition in file periph_conf.h.

#include <stdint.h>
#include "cpu.h"
#include "periph_cpu.h"
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Go to the source code of this file.

External oscillator and clock configuration

For selection of the used CORECLOCK, we have implemented two choices:

  • usage of the PLL fed by the internal 8MHz oscillator divided by 8
  • usage of the internal 8MHz oscillator directly, divided by N if needed

The PLL option allows for the usage of a wider frequency range and a more stable clock with less jitter. This is why we use this option as default.

The target frequency is computed from the PLL multiplier and the PLL divisor. Use the following formula to compute your values:

CORECLOCK = ((PLL_MUL + 1) * 1MHz) / PLL_DIV

NOTE: The PLL circuit does not run with less than 32MHz while the maximum PLL frequency is 96MHz. So PLL_MULL must be between 31 and 95!

The internal Oscillator used directly can lead to a slightly better power efficiency to the cost of a less stable clock. Use this option when you know what you are doing! The actual core frequency is adjusted as follows:

CORECLOCK = 8MHz / DIV

NOTE: A core clock frequency below 1MHz is not recommended

#define CLOCK_USE_PLL   (1)
 
#define CLOCK_PLL_MUL   (47U) /* must be >= 31 & <= 95 */
 
#define CLOCK_PLL_DIV   (1U) /* adjust to your needs */
 
#define CLOCK_CORECLOCK   (((CLOCK_PLL_MUL + 1) * 1000000U) / CLOCK_PLL_DIV)
 

Timer peripheral configuration

#define TIMER_0_MAX_VALUE   0xffff
 
#define TIMER_0_ISR   isr_tc3
 
#define TIMER_1_ISR   isr_tc4
 
#define TIMER_NUMOF   ARRAY_SIZE(timer_config)
 
static const tc32_conf_t timer_config []
 

UART configuration

#define UART_0_ISR   isr_sercom0
 
#define UART_NUMOF   ARRAY_SIZE(uart_config)
 
static const uart_conf_t uart_config []
 

PWM configuration

#define PWM_0_EN   1
 
#define PWM_1_EN   1
 
#define PWM_NUMOF   ARRAY_SIZE(pwm_config)
 
static const pwm_conf_chan_t pwm_chan0_config []
 
static const pwm_conf_chan_t pwm_chan1_config []
 
static const pwm_conf_t pwm_config []
 

ADC configuration

#define ADC_PRESCALER   ADC_CTRLB_PRESCALER_DIV512
 
#define ADC_NEG_INPUT   ADC_INPUTCTRL_MUXNEG_GND
 
#define ADC_GAIN_FACTOR_DEFAULT   ADC_INPUTCTRL_GAIN_1X
 
#define ADC_REF_DEFAULT   ADC_REFCTRL_REFSEL_INT1V
 
#define ADC_NUMOF   ARRAY_SIZE(adc_channels)
 
static const adc_conf_chan_t adc_channels []
 

SPI configuration

#define SPI_NUMOF   ARRAY_SIZE(spi_config)
 
static const spi_conf_t spi_config []
 

I2C configuration

#define I2C_NUMOF   ARRAY_SIZE(i2c_config)
 
static const i2c_conf_t i2c_config []
 

RTT configuration

#define RTT_FREQUENCY   (32768U) /* in Hz. For changes see `rtt.c` */
 

USB peripheral configuration

static const sam0_common_usb_config_t sam_usbdev_config []
 

Variable Documentation

◆ adc_channels

const adc_conf_chan_t adc_channels[]
static
Initial value:
= {
{ GPIO_PIN(PA, 2), ADC_INPUTCTRL_MUXPOS_PIN0 },
{ GPIO_PIN(PB, 8), ADC_INPUTCTRL_MUXPOS_PIN2 },
{ GPIO_PIN(PB, 9), ADC_INPUTCTRL_MUXPOS_PIN3 },
{ GPIO_PIN(PA, 4), ADC_INPUTCTRL_MUXPOS_PIN4 },
{ GPIO_PIN(PA, 5), ADC_INPUTCTRL_MUXPOS_PIN5 },
{ GPIO_PIN(PB, 2), ADC_INPUTCTRL_MUXPOS_PIN10 },
{ GPIO_PIN(PA, 7), ADC_INPUTCTRL_MUXPOS_PIN7 },
}
port B
Definition: periph_cpu.h:93
port A
Definition: periph_cpu.h:92
#define GPIO_PIN(x, y)
Define a CPU specific GPIO pin generator macro.
Definition: periph_cpu.h:35

Definition at line 192 of file periph_conf.h.

◆ i2c_config

const i2c_conf_t i2c_config[]
static
Initial value:
= {
{
.dev = &(SERCOM3->I2CM),
.speed = I2C_SPEED_NORMAL,
.scl_pin = GPIO_PIN(PA, 23),
.sda_pin = GPIO_PIN(PA, 22),
.mux = GPIO_MUX_C,
.gclk_src = SAM0_GCLK_MAIN,
.flags = I2C_FLAG_NONE
}
}
No flags set.
48 MHz main clock
Definition: periph_cpu.h:59
select peripheral function C
port A
Definition: periph_cpu.h:92
#define GPIO_PIN(x, y)
Define a CPU specific GPIO pin generator macro.
Definition: periph_cpu.h:35
normal mode: ~100 kbit/s
Definition: i2c.h:177

Definition at line 236 of file periph_conf.h.

◆ pwm_chan0_config

const pwm_conf_chan_t pwm_chan0_config[]
static
Initial value:
= {
{ GPIO_PIN(PA, 7), GPIO_MUX_E, 1 },
}
select peripheral function E
port A
Definition: periph_cpu.h:92
#define GPIO_PIN(x, y)
Define a CPU specific GPIO pin generator macro.
Definition: periph_cpu.h:35

Definition at line 153 of file periph_conf.h.

◆ pwm_chan1_config

const pwm_conf_chan_t pwm_chan1_config[]
static
Initial value:
= {
{ GPIO_PIN(PA, 16), GPIO_MUX_E, 0 },
}
select peripheral function E
port A
Definition: periph_cpu.h:92
#define GPIO_PIN(x, y)
Define a CPU specific GPIO pin generator macro.
Definition: periph_cpu.h:35

Definition at line 160 of file periph_conf.h.

◆ pwm_config

const pwm_conf_t pwm_config[]
static
Initial value:
= {
{TCC_CONFIG(TCC0), pwm_chan0_config, ARRAY_SIZE(pwm_chan0_config), SAM0_GCLK_MAIN},
{TCC_CONFIG(TCC2), pwm_chan1_config, ARRAY_SIZE(pwm_chan1_config), SAM0_GCLK_MAIN},
}
#define ARRAY_SIZE(a)
Calculate the number of elements in a static array.
48 MHz main clock
Definition: periph_cpu.h:59
#define TCC_CONFIG(tim)
Static initializer for TCC timer configuration.

Definition at line 167 of file periph_conf.h.

◆ sam_usbdev_config

const sam0_common_usb_config_t sam_usbdev_config[]
static
Initial value:
= {
{
.dm = GPIO_PIN(PA, 24),
.dp = GPIO_PIN(PA, 25),
.d_mux = GPIO_MUX_G,
.device = &USB->DEVICE,
.gclk_src = SAM0_GCLK_MAIN,
}
}
48 MHz main clock
Definition: periph_cpu.h:59
select peripheral function G
port A
Definition: periph_cpu.h:92
#define GPIO_PIN(x, y)
Define a CPU specific GPIO pin generator macro.
Definition: periph_cpu.h:35

Definition at line 263 of file periph_conf.h.

◆ spi_config

const spi_conf_t spi_config[]
static
Initial value:
= {
{
.dev = &SERCOM4->SPI,
.miso_pin = GPIO_PIN(PA, 12),
.mosi_pin = GPIO_PIN(PB, 10),
.clk_pin = GPIO_PIN(PB, 11),
.miso_mux = GPIO_MUX_D,
.mosi_mux = GPIO_MUX_D,
.clk_mux = GPIO_MUX_D,
.miso_pad = SPI_PAD_MISO_0,
.mosi_pad = SPI_PAD_MOSI_2_SCK_3,
.gclk_src = SAM0_GCLK_MAIN,
}
}
select peripheral function D
use pad 0 for MISO line
port B
Definition: periph_cpu.h:93
48 MHz main clock
Definition: periph_cpu.h:59
port A
Definition: periph_cpu.h:92
use pad 2 for MOSI, pad 3 for SCK
#define GPIO_PIN(x, y)
Define a CPU specific GPIO pin generator macro.
Definition: periph_cpu.h:35

Definition at line 210 of file periph_conf.h.

◆ timer_config

const tc32_conf_t timer_config[]
static
Initial value:
= {
{
.dev = TC3,
.irq = TC3_IRQn,
.pm_mask = PM_APBCMASK_TC3,
.gclk_ctrl = GCLK_CLKCTRL_ID_TCC2_TC3,
.gclk_src = SAM0_GCLK_1MHZ,
.flags = TC_CTRLA_MODE_COUNT16,
},
{
.dev = TC4,
.irq = TC4_IRQn,
.pm_mask = PM_APBCMASK_TC4 | PM_APBCMASK_TC5,
.gclk_ctrl = GCLK_CLKCTRL_ID_TC4_TC5,
.gclk_src = SAM0_GCLK_1MHZ,
.flags = TC_CTRLA_MODE_COUNT32,
}
}
1 MHz clock for xTimer
Definition: periph_cpu.h:60

Definition at line 81 of file periph_conf.h.

◆ uart_config

const uart_conf_t uart_config[]
static
Initial value:
= {
{
.dev = &SERCOM0->USART,
.rx_pin = GPIO_PIN(PA, 11),
.tx_pin = GPIO_PIN(PA, 10),
.mux = GPIO_MUX_C,
.rx_pad = UART_PAD_RX_3,
.tx_pad = UART_PAD_TX_2,
.flags = UART_FLAG_NONE,
.gclk_src = SAM0_GCLK_MAIN,
}
}
select pad 3
No flags set.
48 MHz main clock
Definition: periph_cpu.h:59
select peripheral function C
select pad 2
port A
Definition: periph_cpu.h:92
#define GPIO_PIN(x, y)
Define a CPU specific GPIO pin generator macro.
Definition: periph_cpu.h:35

Definition at line 121 of file periph_conf.h.