ardupilot/libraries/AP_HAL_ESP32/SoftSigReaderRMT.cpp

157 lines
5.0 KiB
C++
Raw Normal View History

/*
* This file is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This file is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Code by David "Buzz" Bussenschutt and others
*
*/
#if CONFIG_HAL_BOARD == HAL_BOARD_ESP32
#include "SoftSigReaderRMT.h"
using namespace ESP32;
#define RMT_CLK_DIV 10 /*!< RMT counter clock divider */
#define RMT_TICK_US (80000000/RMT_CLK_DIV/1000000) /*!< RMT counter value for 10 us.(Source clock is APB clock) */
#define PPM_IMEOUT_US 3500 /*!< RMT receiver timeout value(us) */
// the RMT peripheral on the esp32 to do this ? looks plausible.
// https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/rmt.html
// with an example here for both transmit and recieve of IR signals:
// https://github.com/espressif/esp-idf/tree/2f8b6cfc7/examples/peripherals/rmt_nec_tx_rx
extern const AP_HAL::HAL& hal;
void SoftSigReaderRMT::init()
{
printf("SoftSigReaderRMT::init\n");
printf("%s\n",__PRETTY_FUNCTION__);
// in case the peripheral was left in a bad state, such as reporting full buffers, this can help clear it, and can be called repeatedly if need be.
//periph_module_reset(PERIPH_RMT_MODULE);
rmt_config_t config;
config.rmt_mode = RMT_MODE_RX;
config.channel = RMT_CHANNEL_0;
2022-11-29 17:54:25 -04:00
#ifndef HAL_ESP32_RMT_RX_PIN_NUMBER
#error HAL_ESP32_RMT_RX_PIN_NUMBER undefined in libraries/AP_HAL_ESP32/boards/esp32... .h
#endif
2022-11-29 17:54:25 -04:00
config.gpio_num = (gpio_num_t)HAL_ESP32_RMT_RX_PIN_NUMBER;
config.clk_div = RMT_CLK_DIV;
config.mem_block_num = 1;
config.rx_config.filter_en = true;
config.rx_config.filter_ticks_thresh = 100;
config.rx_config.idle_threshold = PPM_IMEOUT_US * (RMT_TICK_US);
rmt_config(&config);
rmt_driver_install(config.channel, 1000, 0);
rmt_get_ringbuf_handle(config.channel, &rb);
// we could start it here, but then we get RMT RX BUFFER FULL message will we start calling read()
//rmt_rx_start(config.channel, true);
}
/*
this is what the inside of a rmt_item32_t looks like:
// noting that its 15bits+1bit and another 15bits+ 1bit, so values over 32767 in "duration" bits don't work.
// and the entire size is 32bits
typedef struct rmt_item32_s {
union {
struct {
uint32_t duration0 :15;
uint32_t level0 :1;
uint32_t duration1 :15;
uint32_t level1 :1;
};
uint32_t val;
};
} rmt_item32_t;
*/
bool SoftSigReaderRMT::read(uint32_t &widths0, uint32_t &widths1)
{
//printf("%s\n",__PRETTY_FUNCTION__);
// delayed start till the threads are initialised and we are ready to read() from it....
if (! started ) {
rmt_rx_start(RMT_CHANNEL_0, true);
started = true;
}
size_t rx_size = 0;
static uint32_t channeldata0[16] = { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 }; // don't hardcode this
static uint32_t channeldata1[16] = { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 }; // don't hardcode this
static int channelpointer = -1;
int channels;
// always give priority to handling the RMT queue first
rmt_item32_t* item = (rmt_item32_t*) xRingbufferReceive(rb, &rx_size, 0);
if (item) {
channels = (rx_size / 4) - 1;
//printf("PPM RX %d (%d) channels: ", channels, rx_size);
for (int i = 0; i < channels; i++) {
//printf("%04d ", ((item+i)->duration1 + (item+i)->duration0) / RMT_TICK_US);
channeldata0[i] = ((item+i)->duration0)/RMT_TICK_US;
channeldata1[i] = ((item+i)->duration1)/RMT_TICK_US;
if ( channelpointer < 0 ) {
channelpointer = 0;
}
}
//printf("\n");
vRingbufferReturnItem(rb, (void*) item);
item = nullptr;
}
// each time we are externally called as read() we'll give some return data to the caller.
if ( channelpointer >= 0 ) {
widths0 = uint16_t(channeldata0[channelpointer]);
widths1 = uint16_t(channeldata1[channelpointer]);
//printf(" hi low ch -> %d %d %d\n",width_high,width_low,channelpointer);
channelpointer++;
// in here, after the 8th channel, we're going to re-insert the "wide" pulse that is the idle pulse for ppmsum:
if ( channelpointer == 9 ) {
widths0 = 3000; // must together add up over 2700
widths1 = 1000;
}
if ( channelpointer > 9 ) {
channelpointer = 0;
return false;
}
return true;
}
return false;
}
#endif //CONFIG_HAL_BOARD == HAL_BOARD_ESP32