diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/adccmds.c | 2 | ||||
| -rw-r--r-- | src/sam3x8e/Kconfig | 5 | ||||
| -rw-r--r-- | src/sam3x8e/gpio.c | 76 | ||||
| -rw-r--r-- | src/sam3x8e/gpio.h | 8 |
4 files changed, 90 insertions, 1 deletions
diff --git a/src/adccmds.c b/src/adccmds.c index 907e05d4..49e195ac 100644 --- a/src/adccmds.c +++ b/src/adccmds.c @@ -18,7 +18,7 @@ struct analog_in { uint8_t state, sample_count; }; -static uint8_t +static uint_fast8_t analog_in_event(struct timer *timer) { struct analog_in *a = container_of(timer, struct analog_in, timer); diff --git a/src/sam3x8e/Kconfig b/src/sam3x8e/Kconfig index 00e1f06e..179ac9b7 100644 --- a/src/sam3x8e/Kconfig +++ b/src/sam3x8e/Kconfig @@ -2,6 +2,11 @@ if MACH_SAM3X8E +config SAM_SELECT + bool + default y + select HAVE_GPIO_ADC + config BOARD_DIRECTORY string default "sam3x8e" diff --git a/src/sam3x8e/gpio.c b/src/sam3x8e/gpio.c index 78fb0f05..5445c397 100644 --- a/src/sam3x8e/gpio.c +++ b/src/sam3x8e/gpio.c @@ -5,6 +5,7 @@ // This file may be distributed under the terms of the GNU GPLv3 license. #include <stdint.h> // uint32_t +#include "autoconf.h" // CONFIG_CLOCK_FREQ #include "command.h" // shutdown #include "compiler.h" // ARRAY_SIZE #include "gpio.h" // gpio_out_setup @@ -113,3 +114,78 @@ gpio_in_read(struct gpio_in g) Pio *regs = g.regs; return !!(regs->PIO_PDSR & g.bit); } + + +static const uint8_t adc_pins[] = { + GPIO('A', 2), GPIO('A', 3), GPIO('A', 4), GPIO('A', 6), + GPIO('A', 22), GPIO('A', 23), GPIO('A', 24), GPIO('A', 16), + GPIO('B', 12), GPIO('B', 13), GPIO('B', 17), GPIO('B', 18), + GPIO('B', 19), GPIO('B', 20) +}; + +#define ADC_FREQ_MAX 20000000 +DECL_CONSTANT(ADC_MAX, 4096); + +struct gpio_adc +gpio_adc_setup(uint8_t pin) +{ + int chan; + for (chan=0; chan<ARRAY_SIZE(adc_pins); chan++) { + if (adc_pins[chan] != pin) + continue; + // Found PIN + if (!(PMC->PMC_PCER1 & (1 << (ID_ADC-32)))) { + // Setup ADC + PMC->PMC_PCER1 = 1 << (ID_ADC-32); + uint32_t prescal = SystemCoreClock / (2 * ADC_FREQ_MAX) - 1; + ADC->ADC_MR = (ADC_MR_PRESCAL(prescal) + | ADC_MR_STARTUP_SUT768 + | ADC_MR_TRANSFER(1)); + } + return (struct gpio_adc){ .bit = 1 << chan }; + } + shutdown("Not a valid ADC pin"); +} + +// Try to sample a value. Returns zero if sample ready, otherwise +// returns the number of clock ticks the caller should wait before +// retrying this function. +uint32_t +gpio_adc_sample(struct gpio_adc g) +{ + uint32_t chsr = ADC->ADC_CHSR & 0xffff; + if (!chsr) { + // Start sample + ADC->ADC_CHER = g.bit; + ADC->ADC_CR = ADC_CR_START; + goto need_delay; + } + if (chsr != g.bit) + // Sampling in progress on another channel + goto need_delay; + if (!(ADC->ADC_ISR & ADC_ISR_DRDY)) + // Conversion still in progress + goto need_delay; + // Conversion ready + return 0; +need_delay: + return ADC_FREQ_MAX * 1000ULL / CONFIG_CLOCK_FREQ; +} + +// Read a value; use only after gpio_adc_sample() returns zero +uint16_t +gpio_adc_read(struct gpio_adc g) +{ + ADC->ADC_CHDR = g.bit; + return ADC->ADC_LCDR; +} + +// Cancel a sample that may have been started with gpio_adc_sample() +void +gpio_adc_cancel_sample(struct gpio_adc g) +{ + irqstatus_t flag = irq_save(); + if ((ADC->ADC_CHSR & 0xffff) == g.bit) + gpio_adc_read(g); + irq_restore(flag); +} diff --git a/src/sam3x8e/gpio.h b/src/sam3x8e/gpio.h index d8fdf569..0c75f642 100644 --- a/src/sam3x8e/gpio.h +++ b/src/sam3x8e/gpio.h @@ -20,4 +20,12 @@ struct gpio_in { struct gpio_in gpio_in_setup(uint8_t pin, int8_t pull_up); uint8_t gpio_in_read(struct gpio_in g); +struct gpio_adc { + uint32_t bit; +}; +struct gpio_adc gpio_adc_setup(uint8_t pin); +uint32_t gpio_adc_sample(struct gpio_adc g); +uint16_t gpio_adc_read(struct gpio_adc g); +void gpio_adc_cancel_sample(struct gpio_adc g); + #endif // gpio.h |