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dht_test
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Cleanup code

This commit is contained in:
Arti Zirk 2021-07-08 16:28:32 +03:00
parent e29a4a277a
commit 38e3c715dc
1 changed files with 84 additions and 80 deletions
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164
main.c
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@ -31,18 +31,21 @@
enum DHT11_STATE {
DHT11_STOP, // Stop statemachine
DHT11_BEGIN_START, // We drive DATA Low for min 18ms
DHT11_END_START, // We drive DATA High and set it to input
DHT11_START, // We drive DATA Low for minimum 18ms and then drive it HIGH and start waiting for response
DHT11_RESPONSE, // Wait for DHT to drive DATA Low
DHT11_DATA, // Receiving data
DHT11_END, // Got last bit
DHT11_TIMEOUT, // Not response or data got
DHT11_TIMEOUT, // Not response or got partial data only
};
int g_dht11_state = DHT11_STOP;
int g_dht_i = 0;
uint16_t g_dht_vals[43] = {0};
// 2 pulses are the DHT Response and last 40 are data pulses for 5 bytes
// so we have total of 42 pulses
#define DHT11_BIT_COUNT 42
int g_dht_i = 0; // how many bits we have captured
uint16_t g_dht_vals[DHT11_BIT_COUNT] = {0}; // captured bit times in us
static void delay(int count)
{
@ -64,11 +67,15 @@ static void gpio_setup(void)
// GPIOA_CRH = (GPIO_CNF_OUTPUT_PUSHPULL << (((5 - 8) * 4) + 2));
// GPIOA_CRH |= (GPIO_MODE_OUTPUT_2_MHZ << ((5 - 8) * 4));
/* Using API functions: */
// DHT Data pin
gpio_set_mode(DHT_PORT, GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, DHT_PIN);
// Maple mini led
gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO1);
// A random DEBUG pin we can toggle and measure with logic
gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO2);
}
// Onetime config of timer things that stay the same
static void tim_setup(void)
{
nvic_enable_irq(NVIC_TIM3_IRQ);
@ -77,115 +84,109 @@ static void tim_setup(void)
rcc_periph_clock_enable(RCC_TIM3);
rcc_periph_reset_pulse(RST_TIM3);
// configure the timer to be a normal up counting timer, nothing fancy
timer_set_mode(TIM3, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
timer_set_prescaler(TIM3, (rcc_apb1_frequency*2) / 1000000 - 1); // set timer tickrate to 1mhz
timer_set_period(TIM3, 0xffff);
//timer_one_shot_mode(TIM3);
timer_set_period(TIM3, 0xffff); // ~64 ms, DHT11 packet is never longer than 26ms
timer_ic_set_input(TIM3, TIM_IC3, TIM_IC_IN_TI3);
//timer_ic_set_filter(TIM3, TIM_IC3, 0b1111); // does not do anything ????
//timer_ic_set_polarity(TIM3, TIM_IC3, TIM_IC_FALLING); // TIM_IC_RISING
//timer_ic_enable(TIM3, TIM_IC3);
timer_enable_irq(TIM3, TIM_DIER_UIE);
timer_enable_irq(TIM3, TIM_DIER_CC1IE); // triggered when DHT11_END_START
timer_enable_irq(TIM3, TIM_DIER_UIE); // overflow
timer_enable_irq(TIM3, TIM_DIER_CC3IE); // triggered when DHT drives DATA pin
}
void tim3_isr(void)
{
// Timer overflow that should only happen if DHT11 does not answer
if (timer_get_flag(TIM3, TIM_SR_UIF)) {
timer_clear_flag(TIM3, TIM_SR_UIF);
//gpio_toggle(GPIOB, GPIO2);
if (g_dht11_state == DHT11_RESPONSE) {
puts("no response");
} else if (g_dht11_state == DHT11_DATA) {
puts("got data");
} else {
puts("overflow");
}
puts("overflow");
g_dht11_state = DHT11_TIMEOUT;
timer_disable_counter(TIM3);
//timer_set_counter(TIM3, 0);
//timer_clear_flag(TIM3, TIM_SR_UIF);
//timer_set_oc_value(TIM3, TIM_OC1, 1000);
}
// handle DHT11_END_START
else if (timer_get_flag(TIM3, TIM_SR_CC1IF)) {
timer_clear_flag(TIM3, TIM_SR_CC1IF);
//gpio_toggle(GPIOB, GPIO2);
if (g_dht11_state == DHT11_BEGIN_START) {
g_dht11_state = DHT11_END_START;
// And make the GPIO input so that we can wait for response
gpio_set(DHT_PORT, DHT_PIN);
gpio_set_mode(DHT_PORT, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, DHT_PIN);
// setup timer to wait for start response from dht11
timer_ic_set_polarity(TIM3, TIM_IC3, TIM_IC_FALLING);
timer_clear_flag(TIM3, TIM_SR_CC3IF);
timer_ic_enable(TIM3, TIM_IC3);
//puts("waiting for response");
}
//gpio_toggle(GPIOB, GPIO2);
}
else if (timer_get_flag(TIM3, TIM_SR_CC3IF)) // PB0 changed value
{
gpio_toggle(GPIOB, GPIO2);
//puts("fall");
if (g_dht11_state == DHT11_END_START) {
//gpio_toggle(GPIOB, GPIO2);
// handle DHT11_END_START
if (g_dht11_state == DHT11_START) {
// Drive DATA pin high for a split second so that we have a nice sharp edge
gpio_set(DHT_PORT, DHT_PIN);
// Make the GPIO input so that we can wait for response
// there is a external pull-up connected to the DATA pin
// probably could use the internal pull-up also...
gpio_set_mode(DHT_PORT, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, DHT_PIN);
// setup timer input capture to wait for start response from dht11
// need to disable input capture before we can configure it.
timer_ic_disable(TIM3, TIM_IC3);
timer_ic_set_input(TIM3, TIM_IC3, TIM_IC_IN_TI3);
timer_ic_set_polarity(TIM3, TIM_IC3, TIM_IC_FALLING);
timer_clear_flag(TIM3, TIM_SR_CC3IF); // otherwise we will get a invalid interrupt
timer_ic_enable(TIM3, TIM_IC3);
//puts("waiting for response");
g_dht11_state = DHT11_RESPONSE;
//gpio_toggle(GPIOB, GPIO2);
//timer_ic_disable(TIM3, TIM_IC3);
//timer_clear_flag(TIM3, TIM_SR_CC3IF);
//timer_ic_set_polarity(TIM3, TIM_IC3, TIM_IC_RISING);
g_dht_vals[g_dht_i++] = TIM_CCR3(TIM3); // store captured high time value
//timer_ic_enable(TIM3, TIM_IC3);
//gpio_toggle(GPIOB, GPIO2);
} else {
//gpio_toggle(GPIOB, GPIO2);
g_dht11_state = DHT11_DATA;
g_dht_vals[g_dht_i++] = TIM_CCR3(TIM3); // store length from last sample
//gpio_toggle(GPIOB, GPIO2);
}
if (g_dht_i > 41) {
// we have the whole packet
// DHT11 drove DATA low and has started talking to us
else if (g_dht11_state == DHT11_RESPONSE) {
// store time when DHT11 pulled DATA low
g_dht_vals[g_dht_i++] = TIM_CCR3(TIM3);
g_dht11_state = DHT11_DATA;
}
// DHT11 is sending data to us
else {
// store length of the data bit
g_dht_vals[g_dht_i++] = TIM_CCR3(TIM3);
}
// Did we just capture our last bit?
if (g_dht_i >= DHT11_BIT_COUNT) {
// yes we did
g_dht11_state = DHT11_END;
timer_disable_counter(TIM3);
}
timer_clear_flag(TIM3, TIM_SR_CC3IF);
gpio_toggle(GPIOB, GPIO2);
//gpio_toggle(GPIOB, GPIO2);
}
// if (timer_get_flag(TIM3, TIM_SR_CC3OF))
// {
// timer_clear_flag(TIM3, TIM_SR_CC3OF);
// puts("we are too slow to read and clear timer input capture flags");
// }
// Should only happen if TIM_SR_CC3IF is too slow
// at 72mhz it should never happen but could at lower cpu speeds
if (timer_get_flag(TIM3, TIM_SR_CC3OF))
{
timer_clear_flag(TIM3, TIM_SR_CC3OF);
//puts("we are too slow to read and clear timer input capture flags");
g_dht11_state = DHT11_TIMEOUT;
timer_disable_counter(TIM3);
}
}
// Setup the timer and trigger DHT11 Start
static void dht_start(void)
{
timer_disable_counter(TIM3);
timer_ic_disable(TIM3, TIM_IC3);
g_dht11_state = DHT11_BEGIN_START;
g_dht11_state = DHT11_STOP;
g_dht_i = 0;
// Setup DHT11_END_START trigger on output compare 1
timer_set_counter(TIM3, 0);
timer_set_oc_value(TIM3, TIM_OC1, 1000*20); // 20ms
timer_clear_flag(TIM3, TIM_SR_CC1IF);
timer_clear_flag(TIM3, TIM_SR_CC3IF);
// capture compare channel must be disabled before we can configure it
timer_ic_disable(TIM3, TIM_IC3);
// set channel as output so that we can get an interrupt when OC3 values matches the timer counter
timer_ic_set_input(TIM3, TIM_IC3, TIM_IC_OUT);
// tick rate should be 1Mhz (via timer prescaler), so this should trigger in 20ms
timer_set_oc_value(TIM3, TIM_OC3, 1000*20);
// clear status flags so that we dont get any stray interrupts
timer_clear_flag(TIM3, TIM_SR_CC3IF);
// and make sure that we can get interrupts
timer_ic_enable(TIM3, TIM_IC3);
// Begin the statemachine
g_dht11_state = DHT11_START;
// Do DHT11_BEGIN_START aka drive DATA Low
gpio_set_mode(DHT_PORT, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, DHT_PIN);
@ -193,18 +194,20 @@ static void dht_start(void)
// And start counting
timer_enable_counter(TIM3);
//gpio_toggle(GPIOB, GPIO2);
}
// Parse received DHT11 bit timing data from g_dht_vals and print out pretty values
static void dht_parse_data(){
int8_t data[5] = {0};
uint8_t checksum = 0;
int data_index = 0;
int data_bit = 7;
for (int i=2; i < 42; i++){ // First 2 pulses are start of response, ignore them
// create bytes from bits
for (int i=2; i < DHT11_BIT_COUNT; i++){ // First 2 pulses are start of response, ignore them
uint16_t bit_time = g_dht_vals[i] - g_dht_vals[i-1];
// ~80us is 0 and ~120us is 1
if (bit_time > 100) {
data[data_index] |= 1 << data_bit;
}
@ -227,6 +230,7 @@ static void dht_parse_data(){
}
}
// Just toggle the data pin, used only for debugging
static void dht_start_signal(void)
{
gpio_set_mode(DHT_PORT, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, DHT_PIN);