A7670E sleep

sleep.cpp

/**
 * @file      sleep.ino
 * @author    Lewis He ([email protected])
 * @license   MIT
 * @copyright Copyright (c) 2023  Shenzhen Xin Yuan Electronic Technology Co.,
 * Ltd
 * @date      2023-05-24
 *
 */
#define TINY_GSM_MODEM_SIM7600
#define TINY_GSM_RX_BUFFER 1024 // Set RX buffer to 1Kb
#define SerialAT Serial1

// See all AT commands, if wanted
#undef DUMP_AT_COMMANDS

#include <TinyGsmClient.h>

#define uS_TO_S_FACTOR                                                         \
  1000000ULL             /* Conversion factor for micro seconds to seconds */
#define TIME_TO_SLEEP 30 /* Time ESP32 will go to sleep (in seconds) */

#define UART_BAUD 115200
#define MODEM_RX 27
#define MODEM_TX 26
#define MODEM_PWR 4
#define MODEM_RST 5
#define MODEM_DTR 25
#define BAT_EN 12

#ifdef DUMP_AT_COMMANDS // if enabled it requires the streamDebugger lib
#include <StreamDebugger.h>
StreamDebugger debugger(SerialAT, Serial);
TinyGsm modem(debugger);
#else
TinyGsm modem(SerialAT);
#endif

void setup() {
  Serial.begin(115200); // Set console baud rate

  SerialAT.begin(115200, SERIAL_8N1, MODEM_RX, MODEM_TX);
  delay(100);

  if (esp_sleep_get_wakeup_cause() != ESP_SLEEP_WAKEUP_TIMER) {
    Serial.println("Resetting and powering up modem !");

    pinMode(MODEM_RST, OUTPUT);
    digitalWrite(MODEM_RST, LOW);
    pinMode(MODEM_PWR, OUTPUT);
    digitalWrite(MODEM_PWR, LOW);

    delay(1000);
    digitalWrite(MODEM_RST, HIGH);
    delay(100);
    digitalWrite(MODEM_RST, LOW);
    delay(1000);
    digitalWrite(MODEM_PWR, HIGH);
    delay(100);
    digitalWrite(MODEM_PWR, LOW);

    Serial.println("Let modem do stuff");
    delay(30000);

  } else {
    Serial.println("Wakeup modem !");
    delay(15000);

    // Need to cancel GPIO hold if wake from sleep
    Serial.println("hold disable on dtr");
    gpio_hold_dis((gpio_num_t)MODEM_DTR);
    delay(10000);

    // Pull down DTR to wake up MODEM
    Serial.println("dtr low");
    pinMode(MODEM_DTR, OUTPUT);
    digitalWrite(MODEM_DTR, LOW);
    
    delay(20000);

    modem.sleepEnable(false);
  }

  Serial.println("Check modem online .");
  while (!modem.testAT()) {
    Serial.println(".");
    delay(500);
  }
  Serial.println("Modem is online !");

  Serial.println("Enable deep sleep mode!");

  modem.sendAT("+CSCLK=1");
  if (1 == modem.waitResponse(100, GF("OK"))) {
    Serial.println("SIM76770 deep sleep enabled");
  }

  // Pull up DTR to put the modem into sleep
  pinMode(MODEM_DTR, OUTPUT);
  digitalWrite(MODEM_DTR, HIGH);
  // Set DTR to keep at high level, if not set, DTR will be invalid after ESP32
  // goes to sleep.
  gpio_hold_en((gpio_num_t)MODEM_DTR);
  gpio_deep_sleep_hold_en();

  delay(10000);

  // while (1) {
  modem.sendAT("");
  if (1 == modem.waitResponse(100, GF("OK"))) {
    Serial.println("Modem is still up.");
    delay(1000);
  } else {
    Serial.println("SIM76770 deep sleep enabled");
    // break;
  }
  // }

  Serial.println("Enter esp32 goto deepsleep!");
  esp_sleep_enable_timer_wakeup(TIME_TO_SLEEP * uS_TO_S_FACTOR);
  delay(200);
  esp_deep_sleep_start();
  Serial.println("This will never be printed");
}

void loop() {}

It's v1.1. I have tweaked the timing and added a reset to ensure it boots.

BTW, the modem resets upon esp32 waking up from sleep.