#include "ao.h"
#include "ao_max6691.h"
+#include "ao_exti.h"
-#define cat(a,b) a ## b
+#define cat2(a,b) a ## b
+#define cat(a,b) cat2(a,b)
+
+#if AO_MAX6691_CH != 2
+#error ao_max6691 driver currently only works for timer channel 2
+#endif
#define AO_MAX6691_CCR (AO_MAX6691_TIMER->cat(ccr, AO_MAX6691_CH))
-#if 0
-static uint16_t ao_max6691_data[8];
+/* Two samples per channel, plus time start value and two for Tready pulse */
+
+#define AO_MAX6691_SAMPLES (AO_MAX6691_CHANNELS * 2 + 3)
+
+static uint16_t ao_max6691_raw[AO_MAX6691_SAMPLES];
+
+static inline uint16_t
+ao_max6691_t_high(int channel)
+{
+ return ao_max6691_raw[channel * 2 + 3] - ao_max6691_raw[channel * 2 + 2];
+}
+
+static inline uint16_t
+ao_max6691_t_low(int channel)
+{
+ return ao_max6691_raw[channel * 2 + 4] - ao_max6691_raw[channel * 2 + 3];
+}
void
-ao_max6691_sample(void)
+ao_max6691_sample(struct ao_max6691 *ao_max6691)
{
+ struct stm_tim234 *tim = AO_MAX6691_TIMER;
+
+ tim->sr = 0;
+
+ memset(&ao_max6691_raw, '\0', sizeof (ao_max6691_raw));
/* Get the DMA engine ready */
ao_dma_set_transfer(AO_MAX6691_DMA,
&AO_MAX6691_CCR,
- &ao_max6691_data,
- 8,
+ &ao_max6691_raw,
+ AO_MAX6691_SAMPLES,
(0 << STM_DMA_CCR_MEM2MEM) |
(STM_DMA_CCR_PL_MEDIUM << STM_DMA_CCR_PL) |
(STM_DMA_CCR_MSIZE_16 << STM_DMA_CCR_MSIZE) |
ao_dma_start(AO_MAX6691_DMA);
/* Prod the max6691 */
- ao_gpio_set(AO_MAX6691_PORT, AO_MAX6691_PIN, 0);
- ao_arch_nop();
- ao_gpio_set(AO_MAX6691_PORT, AO_MAX6691_PIN, 1);
+ ao_set_output(AO_MAX6691_GPIO, AO_MAX6691_PIN, 0);
+ int i;
+ for (i = 0; i < 100; i++)
+ ao_arch_nop();
+ ao_set_input(AO_MAX6691_GPIO, AO_MAX6691_PIN);
+ for (i = 0; i < 100; i++)
+ ao_arch_nop();
+
+ /* Reset the timer count */
+ tim->cnt = 0;
/* Switch the pin to timer input mode */
stm_afr_set(AO_MAX6691_GPIO, AO_MAX6691_PIN, STM_AFR_AF1);
+ tim->ccer = ((0 << STM_TIM234_CCER_CC1E) |
+ (0 << STM_TIM234_CCER_CC1P) |
+ (0 << STM_TIM234_CCER_CC1NP) |
+ (1 << STM_TIM234_CCER_CC2E) |
+ (1 << STM_TIM234_CCER_CC2P) |
+ (1 << STM_TIM234_CCER_CC2NP) |
+ (0 << STM_TIM234_CCER_CC3E) |
+ (0 << STM_TIM234_CCER_CC3P) |
+ (0 << STM_TIM234_CCER_CC3NP) |
+ (0 << STM_TIM234_CCER_CC4E) |
+ (0 << STM_TIM234_CCER_CC4P) |
+ (0 << STM_TIM234_CCER_CC4NP));
+
+ /* Enable event generation on channel 2 */
+
+ tim->egr = ((0 << STM_TIM234_EGR_TG) |
+ (0 << STM_TIM234_EGR_CC4G) |
+ (0 << STM_TIM234_EGR_CC3G) |
+ (1 << STM_TIM234_EGR_CC2G) |
+ (0 << STM_TIM234_EGR_CC1G) |
+ (0 << STM_TIM234_EGR_UG));
+ /* Start the timer */
+ tim->cr1 |= (1 << STM_TIM234_CR1_CEN);
+
ao_arch_block_interrupts();
- while (!ao_dma_done(AO_MAX6691_DMA))
- ao_sleep(&ao_dma_done(AO_MAX6691_DMA));
+ while (!ao_dma_done[AO_MAX6691_DMA])
+ ao_sleep(&ao_dma_done[AO_MAX6691_DMA]);
ao_arch_release_interrupts();
- /* Switch pin back to output mode */
- stm_moder_set(AO_MAX6691_GPIO, AO_MAX6691_PIN, STM_MODER_OUTPUT);
+ /* Disable event generation */
+ tim->egr = 0;
+
+ /* Disable capture */
+ tim->ccer = 0;
+
+ /* Stop the timer */
+ tim->cr1 &= ~(1 << STM_TIM234_CR1_CEN);
+
+ /* Switch back to GPIO mode */
+ stm_moder_set(AO_MAX6691_GPIO, AO_MAX6691_PIN, STM_MODER_INPUT);
/* Mark DMA done */
ao_dma_done_transfer(AO_MAX6691_DMA);
+
+ for (i = 0; i < AO_MAX6691_CHANNELS; i++) {
+ ao_max6691->sensor[i].t_high = ao_max6691_t_high(i);
+ ao_max6691->sensor[i].t_low = ao_max6691_t_low(i);
+ }
}
-#endif
+
+#define R_EXT 1000.0f
static void
ao_max6691_test(void)
{
- int i;
+ struct ao_max6691 ao_max6691;
- printf("Testing MAX6691\n");
- /* Prod the max6691 */
- ao_set_output(AO_MAX6691_GPIO, AO_MAX6691_PIN, 0);
- for (i = 0; i < 1000; i++) {
- ao_led_on(AO_LED_ARMED);
- ao_gpio_set(AO_MAX6691_GPIO, AO_MAX6691_PIN, 0);
- ao_delay(AO_MS_TO_TICKS(250));
- ao_led_off(AO_LED_ARMED);
- ao_gpio_set(AO_MAX6691_GPIO, AO_MAX6691_PIN, 1);
- ao_delay(AO_MS_TO_TICKS(250));
- }
-#if 0
- uint16_t tick;
- uint16_t i, j;
- uint8_t p, v;
+ printf("Testing MAX6691\n"); flush();
+ ao_max6691_sample(&ao_max6691);
- for (i = 0; i < 100; i++)
- ao_arch_nop();
- ao_gpio_set(AO_MAX6691_GPIO, AO_MAX6691_PIN, 1);
- ao_arch_nop();
- ao_set_input(AO_MAX6691_GPIO, AO_MAX6691_PIN);
- i = 0;
- p = 1;
- for (tick = 0; i < 8 && tick < 10000; tick++)
- {
- v = ao_gpio_get(AO_MAX6691_GPIO, AO_MAX6691_PIN);
- if (v != p) {
- ao_max6691_data[i++] = tick;
- p = v;
- }
+ int i;
+ for (i = 0; i < AO_MAX6691_SAMPLES; i++)
+ printf("%d: %5u\n", i, ao_max6691_raw[i]);
+
+ for (i = 0; i < AO_MAX6691_CHANNELS; i++) {
+ uint16_t t_high = ao_max6691.sensor[i].t_high;
+ uint16_t t_low = ao_max6691.sensor[i].t_low;
+
+ /*
+ * From the MAX6691 data sheet
+ *
+ * Thigh Vext Rext
+ * ----- = ---- - 0.0002 = ---------- - 0.0002
+ * Tlow Vref Rext - Rth
+ *
+ * We want to find Rth given Rext and the timing values
+ *
+ * Thigh Rext
+ * ----- + 0.0002 = ----------
+ * Tlow Rext + Rth
+ *
+ * V = (Thigh / Tlow + 0.0002)
+ *
+ * (Rext + Rth) * V = Rext
+ *
+ * Rext * V + Rth * V = Rext
+ *
+ * Rth * V = Rext - Rext * V
+ *
+ * Rth * V = Rext * (1 - V)
+ *
+ * Rth = Rext * (1 - V) / V
+ */
+
+ float V = (float) t_high / (float) t_low + 0.0002f;
+
+ float Rth = R_EXT * (1 - V) / V;
+
+ printf("%d: high %5u low %5u ohms: %7g\n", i, t_high, t_low, Rth);
}
- for (j = 0; j < i; i++)
- printf("%d: %5u\n", j, ao_max6691_data[j]);
-#endif
- printf("Done\n");
}
static const struct ao_cmds ao_max6691_cmds[] = {
{
ao_cmd_register(&ao_max6691_cmds[0]);
-#if 0
- struct stm_tim234 *tim = &AO_MAX6691_TIMER;
+ struct stm_tim234 *tim = AO_MAX6691_TIMER;
stm_rcc.apb1enr |= (1 << AO_MAX6691_TIMER_ENABLE);
tim->cr1 = 0;
- tim->psc = 0;
+ tim->psc = (AO_TIM23467_CLK / 4000000) - 1; /* run the timer at 4MHz */
tim->cnt = 0;
- tim->ccmr1 = ((0 << STM_TIM234_CCMR1_IC2F) |
- (
+ /*
+ * XXX This assumes we're using CH2, which is true on TeleFireOne v2.0
+ */
+ tim->ccmr1 = ((STM_TIM234_CCMR1_IC2F_NONE << STM_TIM234_CCMR1_IC2F) |
+ (STM_TIM234_CCMR1_IC2PSC_NONE << STM_TIM234_CCMR1_IC2PSC) |
+ (STM_TIM234_CCMR1_CC2S_INPUT_TI2 << STM_TIM234_CCMR1_CC2S));
-
- tim->ccmr2 = ((0 << STM_TIM234_CCMR2_OC4CE) |
- (STM_TIM234_CCMR2_OC4M_PWM_MODE_1 << STM_TIM234_CCMR2_OC4M) |
- (0 << STM_TIM234_CCMR2_OC4PE) |
- (0 << STM_TIM234_CCMR2_OC4FE) |
- (STM_TIM234_CCMR2_CC4S_OUTPUT << STM_TIM234_CCMR2_CC4S) |
-
- (0 << STM_TIM234_CCMR2_OC3CE) |
- (STM_TIM234_CCMR2_OC3M_PWM_MODE_1 << STM_TIM234_CCMR2_OC3M) |
- (0 << STM_TIM234_CCMR2_OC3PE) |
- (0 << STM_TIM234_CCMR2_OC3FE) |
- (STM_TIM234_CCMR2_CC3S_OUTPUT << STM_TIM234_CCMR2_CC3S));
- tim->ccer = ((1 << STM_TIM234_CCER_CC1E) |
- (0 << STM_TIM234_CCER_CC1P) |
- (1 << STM_TIM234_CCER_CC2E) |
- (0 << STM_TIM234_CCER_CC2P) |
- (1 << STM_TIM234_CCER_CC3E) |
- (0 << STM_TIM234_CCER_CC3P) |
- (1 << STM_TIM234_CCER_CC4E) |
- (0 << STM_TIM234_CCER_CC4P));
-
- tim->egr = 0;
+ tim->ccer = 0;
tim->sr = 0;
tim->dier = 0;
(STM_TIM234_CR2_MMS_RESET<< STM_TIM234_CR2_MMS) |
(0 << STM_TIM234_CR2_CCDS));
- tim->cr1 = ((STM_TIM234_CR1_CKD_1 << STM_TIM234_CR1_CKD) |
- (0 << STM_TIM234_CR1_ARPE) |
- (STM_TIM234_CR1_CMS_EDGE << STM_TIM234_CR1_CMS) |
- (STM_TIM234_CR1_DIR_UP << STM_TIM234_CR1_DIR) |
- (0 << STM_TIM234_CR1_OPM) |
- (0 << STM_TIM234_CR1_URS) |
- (0 << STM_TIM234_CR1_UDIS) |
- (1 << STM_TIM234_CR1_CEN));
-
- tim->cr2 = ((0 << STM_TIM234_CR2_TI1S) |
- (STM_TIM234_CR2_MMS_RESET << STM_TIM234_CR2_MMS) |
- (0 << STM_TIM234_CR2_CCDS));
-
tim->dier = ((0 << STM_TIM234_DIER_TDE) |
(0 << STM_TIM234_DIER_CC4DE) |
(0 << STM_TIM234_DIER_CC3DE) |
(0 << STM_TIM234_DIER_CC1IE) |
(0 << STM_TIM234_DIER_UIE));
- tim->egr = ((0 << STM_TIM234_EGR_TG) |
- (0 << STM_TIM234_EGR_CC4G) |
- (0 << STM_TIM234_EGR_CC3G) |
- (1 << STM_TIM234_EGR_CC2G) |
- (0 << STM_TIM234_EGR_CC1G) |
- (0 << STM_TIM234_EGR_UG));
+ tim->egr = 0;
- tim->ccmr1 = ((0 << STM_TIM234_CCMR_IC2F) |
- (0 << STM_TIM234_CCMR_IC2PSC) |
- (2 << STM_TIM234_CCMR_CC2S) |
- (
+ tim->cr1 = ((STM_TIM234_CR1_CKD_1 << STM_TIM234_CR1_CKD) |
+ (0 << STM_TIM234_CR1_ARPE) |
+ (STM_TIM234_CR1_CMS_EDGE << STM_TIM234_CR1_CMS) |
+ (STM_TIM234_CR1_DIR_UP << STM_TIM234_CR1_DIR) |
+ (0 << STM_TIM234_CR1_OPM) |
+ (0 << STM_TIM234_CR1_URS) |
+ (0 << STM_TIM234_CR1_UDIS) |
+ (0 << STM_TIM234_CR1_CEN));
stm_ospeedr_set(AO_MAX6691_GPIO, AO_MAX6691_PIN, STM_OSPEEDR_40MHz);
-#endif
- ao_enable_output(AO_MAX6691_GPIO, AO_MAX6691_PIN, 1);
+ ao_enable_input(AO_MAX6691_GPIO, AO_MAX6691_PIN, AO_EXTI_MODE_PULL_UP);
}
projects / fw / altos / blobdiff