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#34 The Robot app is now able to receive a range command from the Gat…
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…eway and send back the US range measurement
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@trifuns @aabadie
trifuns authored and aabadie committed Jun 23, 2022
1 parent 816304f commit 70fc04c
Showing 1 changed file with 191 additions and 31 deletions.
222 changes: 191 additions & 31 deletions projects/03app_us_ranging/03app_us_ranging.c
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Original file line number Diff line number Diff line change
Expand Up @@ -24,11 +24,21 @@
//=========================== defines ===========================================

// Defines for setting up the trigger pulse width and frequency
#define PULSE_DURATION_MS 0.01
#define PULSE_OFFSET_MS 200
#define PULSE_DURATION_MS 0.01
#define PULSE_OFFSET_MS 200

// Defines for the Radio
#define NUMBER_OF_BYTES_IN_PACKET 32
#define NUMBER_OF_BYTES_IN_PACKET 32

// First byte in the Gateway message which correspond to the US ranging app type
#define ID_RANGE_ALL 0x11
#define ID_RANGE_PAIR 0x22
#define ID_RANGE_NONE 0xff

// Robot ID will be used as a uniqe identifier or Address of a robot
#define ROBOT_ID 0x01
// Gateway ID will be used as a uniqe identifier or Address of a robot
#define GATEWAY_ID 0x77

//=========================== prototypes =========================================

Expand All @@ -42,12 +52,39 @@ void radio_callback(uint8_t *packet, uint8_t length);

//=========================== variables =========================================

enum {
APP_FLAG_RADIO_RX = 0x01, // Flag for indicating end of frame
APP_FLAG_RTC = 0x02, // Flag for indicating RTC timer event
APP_FLAG_US_DONE = 0x04, // Flag to indicate that a new US ranging is done
} app_flags_t;

typedef enum {
RADIO_Tx = 0x01, // To know when the Radio is sending the packet
RADIO_Rx = 0x02, // To know when the Radio is receiving the packet
RADIO_Idle = 0x04, // To know when the Radio is Idle
} app_radio_mode_t;

typedef enum {
RANGE_ALL = 0x01, // State that represents the experiment where all robots range at a time
RANGE_PAIR = 0x02, // State that represents the experiment where two robots range at a time
RANGE_NONE = 0x04, // State where no ranging measurements are performed
} app_state_t;

typedef struct {
NRF_TIMER_Type *timer0; // Pointer to the TIMER structure used for triggering US sensor
NRF_TIMER_Type *timer1; // Pointer to the TIMER structure used for reading the range on the US sensor
NRF_TIMER_Type *timer0; // Pointer to the TIMER structure used for triggering US sensor
NRF_TIMER_Type *timer1; // Pointer to the TIMER structure used for reading the range on the US sensor

double trigger_duration_ms;
uint32_t trigger_offset_ms;

app_state_t state; // Variable for storing the state of the ranging app

volatile uint8_t flag; // Stores the app flags

uint8_t packet_tx[NUMBER_OF_BYTES_IN_PACKET]; // Radio packet Tx
uint8_t packet_rx[NUMBER_OF_BYTES_IN_PACKET]; // Radio packet Rx
app_radio_mode_t radio_mode; // Stores the current Radio mode

uint8_t packet_tx[NUMBER_OF_BYTES_IN_PACKET]; // Radio packet Tx
uint8_t packet_rx[NUMBER_OF_BYTES_IN_PACKET]; // Radio packet Rx
} app_vars_t;

static app_vars_t app_vars;
Expand All @@ -58,11 +95,21 @@ static app_vars_t app_vars;
* @brief The program starts executing here.
*/
int main(void) {

// For debug Set the test pin (P0.31) as an output
NRF_P0->PIN_CNF[31] = (GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos) | // Set Pin as output
(GPIO_PIN_CNF_DRIVE_S0S1 << GPIO_PIN_CNF_DRIVE_Pos); // Activate high current gpio mode.

memset(&app_vars, 0, sizeof(app_vars_t));

app_vars.timer0 = NRF_TIMER0;
app_vars.timer1 = NRF_TIMER1;
// Initialize timers for US ON and US READ
app_vars.timer0 = NRF_TIMER0;
app_vars.timer1 = NRF_TIMER1;

app_vars.trigger_duration_ms = PULSE_DURATION_MS;
app_vars.trigger_offset_ms = PULSE_OFFSET_MS;

app_vars.state = RANGE_NONE;

// uncomment if using this code on DotBot Turn ON the DotBot board regulator
db_board_init();
Expand All @@ -72,27 +119,94 @@ int main(void) {
db_radio_init_lr(&radio_callback); // Set radio callback and initialize Long Range BLE
db_radio_set_frequency(8); // Set the RX frquency to 2408 MHz.

db_radio_tx(app_vars.packet_tx, NUMBER_OF_BYTES_IN_PACKET);
db_radio_rx_enable(); // Start receiving packets.

app_vars.radio_mode = RADIO_Rx; // RX mode by default

//=========================== Configure HC_SR04 =========================================

// initilize the US sensor, set callback and chose the timers
// initilize the US sensor, set callback and choose the timers
hc_sr04_init(&us_callback, &timer_callback, app_vars.timer0, app_vars.timer1);

// initial timer settings for the trigger pulse
hc_sr04_on_set_trigger(PULSE_DURATION_MS, PULSE_OFFSET_MS);

// start high frequency clock needed for PPI
hfclk_init();

// start ranging
hc_sr04_start();

while (1) {
__WFE();
__SEV();
__WFE();

// Board sleep if no event flag is set
while (app_vars.flag == 0x00) {
// Let's go to sleep
// See https://devzone.nordicsemi.com/f/nordic-q-a/49010/methods-to-put-the-nrf52-to-sleep-in-a-spinlock-loop
// for details
__WFE();
__SEV();
__WFE();
}

//TODO disable int
// handle and clear the event flags
switch(app_vars.state) {
/*
* RANGE_NONE is the mode of the app where the
* gateway sent instruction to stop the ranging
*/
case RANGE_NONE:
if ((app_vars.flag == APP_FLAG_RADIO_RX) && (app_vars.radio_mode == RADIO_Rx)) {
// stop ranging
hc_sr04_stop();
}
break;
/*
* RANGE_ALL is the mode of the app where the gateway allows the
* ranging of all robots at the same time
* with given offset
*/
case RANGE_ALL:
switch (app_vars.flag) {
case APP_FLAG_RADIO_RX: // check if the Robot received a packet from the Gateway
if (app_vars.radio_mode == RADIO_Rx) {
db_radio_rx_disable(); // Disable the radio
app_vars.radio_mode = RADIO_Idle; // Set the radio mode to Idle
}
break;
case APP_FLAG_US_DONE: // check if we have a new US reading
//TODO START RTC
app_vars.radio_mode = RADIO_Tx; // set the Radio mode to Tx

hc_sr04_stop(); // stop the ranging we already have a measurement

db_radio_tx(app_vars.packet_tx, NUMBER_OF_BYTES_IN_PACKET); // send the US reading with ROBOT ID to Gateway
memset(app_vars.packet_tx, 0, sizeof(app_vars.packet_tx)); // clear the buffer

db_radio_rx_enable(); // enable the Radio packet reception
app_vars.radio_mode = RADIO_Rx; // set the Radio mode to Rx

break;
case APP_FLAG_RTC: // ready to send a packet with US measurement
if (app_vars.radio_mode == RADIO_Tx) {
//db_radio_tx(app_vars.packet_tx, NUMBER_OF_BYTES_IN_PACKET);
app_vars.radio_mode = RADIO_Rx;
//TODO
}
break;
default:
break;
}
//TODO
break; // RANGE ALL case break
/*
* RANGE_PAIR is the mode of the app where the gateway allows the
* ranging of pairs of robots at different time slots
*/
case RANGE_PAIR:
//TODO
break; // RANGE PAIR case break

default:
// stop ranging
hc_sr04_stop();
break;
}
// clear flag
app_vars.flag = 0x00;
//TODO enable int
}
// one last instruction, doesn't do anything, it's just to have a place to put a breakpoint.
__NOP();
Expand All @@ -110,21 +224,67 @@ int main(void) {
*
*/
void radio_callback(uint8_t *packet, uint8_t length) {
// check if the packet is received and if it is from the Gateway
if((app_vars.radio_mode == RADIO_Rx) && (packet[0] == GATEWAY_ID)) {

// stop ranging
hc_sr04_stop();

// start ranging
hc_sr04_start();

// set the flag for the packet reception
app_vars.flag = APP_FLAG_RADIO_RX;

// check the mode of operation sent by the Gateway
switch (packet[1]) {
case ID_RANGE_NONE:
app_vars.state = RANGE_NONE;
break;
case ID_RANGE_ALL:
app_vars.state = RANGE_ALL;
break;
case ID_RANGE_PAIR:
app_vars.state = RANGE_PAIR;
break;
default:
app_vars.state = RANGE_NONE;
break;
}

if (app_vars.state == RANGE_ALL) {

app_vars.trigger_offset_ms = packet[2] ;
app_vars.trigger_offset_ms |= packet[3] << 8;
app_vars.trigger_offset_ms |= packet[4] << 16;
app_vars.trigger_offset_ms |= packet[5] << 24;

hc_sr04_on_set_trigger(app_vars.trigger_duration_ms, (double)app_vars.trigger_offset_ms);

hc_sr04_start();
NRF_P0->OUTSET = 1 << GPIO_OUTSET_PIN31_Pos; // ranging started set the pin HIGH.
}
else if (app_vars.state == RANGE_PAIR) {
//TODO
}
}
}

/**
* @brief This is a callback for US reading.
* The code ends up here every time a new measurement is taken. The new measurement is stored in us_reading argument
*/
void us_callback(uint32_t us_reading) {
__NOP();

// set the flag indicating that we got a new US measurement
app_vars.flag = APP_FLAG_US_DONE;

// prepare the packet to send to a gateway
app_vars.packet_tx[0] = ROBOT_ID;

app_vars.packet_tx[1] = us_reading;
app_vars.packet_tx[2] = us_reading >> 8;
app_vars.packet_tx[3] = us_reading >> 16;
app_vars.packet_tx[4] = us_reading >> 24;

app_vars.packet_tx[5] = 0xff;

app_vars.packet_tx[6] = '\r';
app_vars.packet_tx[7] = '\n';
}

/**
Expand All @@ -133,5 +293,5 @@ void us_callback(uint32_t us_reading) {
* We could change the pulse_offset_ms here by writting a new value to timer0->CC[0] and timer0->CC[1]
*/
void timer_callback(void) {
__NOP();
NRF_P0->OUTCLR = 1 << GPIO_OUTCLR_PIN31_Pos; // US trigger pulse finish set the pin LOW.
}

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