32bit and 64bit microseconds counters on ESP32-S3. Undocumented.

gistfile1.txt

// Example for ESP32-S3: two ways to read a microsecond timestamp.
//
// 1. Very fast, but returns only the lower 32 bits
// 2. Full 64-bit timestamp, slightly slower
//
// For simplicity, this example uses the Arduino framework.
//
// vvb333007@gmail.com
//
//
#include <Arduino.h>
#include <stdint.h>

// Timer command register
#define WIFI_TSF_CMD_REG (volatile uint32_t *)((uintptr_t)0x6003500c)
#  define WIFI_TSFC_LATCH 1 // Latch current counter values into MMIO registers

// Latched 64-bit counter value
#define WIFI_TSF_HIGH_REG (volatile uint32_t *)((uintptr_t)0x6003501c)
#define WIFI_TSF_LOW_REG  (volatile uint32_t *)((uintptr_t)0x60035018)

// Free-running 32-bit microsecond counter
#define WIFI_MICROS_REG (volatile uint32_t *)((uintptr_t)0x60035000)

// Fastest possible micros() implementation
//
uint32_t micros32() {
  return *WIFI_MICROS_REG;
}

// Full 64-bit microsecond timestamp
// The logic is straightforward enough to not need much explanation
//
uint64_t micros64() {

  uint32_t low, high;

  // create snapshot
  *WIFI_TSF_CMD_REG |= WIFI_TSFC_LATCH;

  low = *WIFI_TSF_LOW_REG;
  high = *WIFI_TSF_HIGH_REG;

  *WIFI_TSF_CMD_REG &= ~WIFI_TSFC_LATCH;

  // make 64bit result
  return (((uint64_t)high) << 32) | (uint64_t)low;
}

void setup() {

  Serial.begin(115200);
}

void loop() {

  delay(1000);

  Serial.printf("%llu , %lu\r\n", micros64(), micros32());
}