Configuration of CPU peripherals for the Atmel SAM D20 Xplained Pro board.
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#include <stdint.h>
#include "cpu.h"
#include "periph_cpu.h"
Go to the source code of this file.
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There are three choices for selection of CORECLOCK:
- usage of the 48 MHz DFLL fed by external oscillator running at 32 kHz
- 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 this option is 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
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| #define | CLOCK_USE_PLL (0) |
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| #define | CLOCK_USE_XOSC32_DFLL (1) |
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| #define | GEN2_ULP32K (0) |
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| #define | CLOCK_DIV (1U) |
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| #define | CLOCK_CORECLOCK (8000000 / CLOCK_DIV) |
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| #define | RTT_FREQUENCY (32768U) /* in Hz. For changes see `rtt.c` */ |
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◆ ADC_GAIN_FACTOR_DEFAULT
| #define ADC_GAIN_FACTOR_DEFAULT ADC_INPUTCTRL_GAIN_1X |
◆ ADC_NEG_INPUT
| #define ADC_NEG_INPUT ADC_INPUTCTRL_MUXNEG_GND |
◆ ADC_NUMOF
◆ ADC_PRESCALER
| #define ADC_PRESCALER ADC_CTRLB_PRESCALER_DIV128 |
◆ ADC_REF_DEFAULT
| #define ADC_REF_DEFAULT ADC_REFCTRL_REFSEL_INT1V |
◆ CLOCK_CORECLOCK
| #define CLOCK_CORECLOCK (8000000 / CLOCK_DIV) |
◆ CLOCK_DIV
◆ CLOCK_USE_PLL
| #define CLOCK_USE_PLL (0) |
◆ CLOCK_USE_XOSC32_DFLL
| #define CLOCK_USE_XOSC32_DFLL (1) |
◆ DAC_CLOCK
◆ DAC_VREF
| #define DAC_VREF DAC_CTRLB_REFSEL_AVCC |
◆ GEN2_ULP32K
◆ I2C_NUMOF
◆ PWM_0_EN
◆ PWM_NUMOF
◆ RTT_FREQUENCY
| #define RTT_FREQUENCY (32768U) /* in Hz. For changes see `rtt.c` */ |
◆ SPI_NUMOF
◆ TIMER_0_ISR
| #define TIMER_0_ISR isr_tc0 |
◆ TIMER_1_ISR
| #define TIMER_1_ISR isr_tc4 |
◆ TIMER_NUMOF
◆ UART_0_ISR
| #define UART_0_ISR isr_sercom3 |
◆ UART_1_ISR
| #define UART_1_ISR isr_sercom4 |
◆ UART_2_ISR
| #define UART_2_ISR isr_sercom0 |
◆ UART_NUMOF
◆ adc_channels
Initial value:= {
}
#define ADC_INPUTCTRL_MUXPOS_PA10
Alias for PIN18.
#define ADC_INPUTCTRL_MUXPOS_PA11
Alias for PIN19.
#define ADC_INPUTCTRL_MUXPOS_PB01
Alias for PIN9.
#define ADC_INPUTCTRL_MUXPOS_PA02
ADC pin aliases.
#define ADC_INPUTCTRL_MUXPOS_PA03
Alias for PIN1.
#define ADC_INPUTCTRL_MUXPOS_PB00
Alias for PIN8.
Definition at line 305 of file periph_conf.h.
◆ i2c_config
Initial value:= {
{
.dev = &(SERCOM2->I2CM),
}
}
#define GPIO_PIN(x, y)
Define a CPU specific GPIO pin generator macro.
@ I2C_SPEED_NORMAL
normal mode: ~100 kbit/s
@ I2C_FLAG_NONE
No flags set.
@ GPIO_MUX_D
select peripheral function D
#define SAM0_GCLK_MAIN
120 MHz main clock
Definition at line 241 of file periph_conf.h.
◆ pwm_config
◆ spi_config
◆ timer_config
Initial value:= {
{
.dev = TC0,
.irq = TC0_IRQn,
.pm_mask = PM_APBCMASK_TC0 | PM_APBCMASK_TC1,
.gclk_ctrl = GCLK_CLKCTRL_ID_TC0_TC1,
.flags = TC_CTRLA_MODE_COUNT32,
},
{
.dev = TC4,
.irq = TC4_IRQn,
.pm_mask = PM_APBCMASK_TC4 | PM_APBCMASK_TC5,
.gclk_ctrl = GCLK_CLKCTRL_ID_TC4_TC5,
.flags = TC_CTRLA_MODE_COUNT32,
}
}
Definition at line 100 of file periph_conf.h.
◆ uart_config
Include dependency graph for periph_conf.h: