Configuration of CPU peripherals for SenseBox MCU with SAMD21.
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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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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
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| #define | CLOCK_USE_PLL (1) |
| |
| #define | CLOCK_DIV (1U) |
| |
| #define | CLOCK_CORECLOCK (8000000 / CLOCK_DIV) |
| |
|
| #define | RTT_FREQUENCY (32768U) /* in Hz. For changes see `rtc_rtt.c` */ |
| |
◆ 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_DIV512 |
◆ 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 (1) |
◆ I2C_NUMOF
◆ RTT_FREQUENCY
| #define RTT_FREQUENCY (32768U) /* in Hz. For changes see `rtc_rtt.c` */ |
◆ SPI_NUMOF
◆ TIMER_0_ISR
| #define TIMER_0_ISR isr_tc3 |
◆ TIMER_0_MAX_VALUE
| #define TIMER_0_MAX_VALUE 0xffff |
◆ 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_NUMOF
◆ adc_channels
Initial value:= {
}
#define ADC_INPUTCTRL_MUXPOS_PA05
Alias for PIN5.
#define ADC_INPUTCTRL_MUXPOS_PA07
Alias for PIN7.
#define ADC_INPUTCTRL_MUXPOS_PA04
Alias for PIN4.
#define ADC_INPUTCTRL_MUXPOS_PA06
Alias for PIN6.
#define ADC_INPUTCTRL_MUXPOS_PA02
ADC pin aliases.
#define ADC_INPUTCTRL_MUXPOS_PA03
Alias for PIN1.
Definition at line 236 of file periph_conf.h.
◆ i2c_config
Initial value:= {
{
.dev = &(SERCOM0->I2CM),
},
{
.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_C
select peripheral function C
#define SAM0_GCLK_MAIN
120 MHz main clock
Definition at line 190 of file periph_conf.h.
◆ sam_usbdev_config
Initial value:= {
{
.device = &USB->DEVICE,
}
}
@ GPIO_MUX_G
select peripheral function G
Definition at line 253 of file periph_conf.h.
◆ spi_config
Initial value:= {
{
.dev = &SERCOM1->SPI,
}
}
@ SPI_PAD_MISO_3
use pad 3 for MISO line
@ SPI_PAD_MOSI_0_SCK_1
use pad 0 for MOSI, pad 1 for SCK
Definition at line 164 of file periph_conf.h.
◆ timer_config
Initial value:= {
{
.dev = TC3,
.irq = TC3_IRQn,
.pm_mask = PM_APBCMASK_TC3,
.gclk_ctrl = GCLK_CLKCTRL_ID_TCC2_TC3,
.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,
.flags = TC_CTRLA_MODE_COUNT32,
}
}
Definition at line 82 of file periph_conf.h.
◆ uart_config
Initial value:= {
{
.dev = &SERCOM3->USART,
},
{
.dev = &SERCOM4->USART,
}
}
@ UART_PAD_RX_1
select pad 1
@ UART_FLAG_NONE
No flags set.
@ UART_PAD_TX_0
select pad 0
@ GPIO_MUX_D
select peripheral function D
Definition at line 122 of file periph_conf.h.
Include dependency graph for periph_conf.h: