Fix 18CH auto-SMUX: single start, burst read all registers

readAllChannels() was calling startMeasurement() per cycle, resetting
the auto-SMUX counter. Per datasheet, SP_EN is set once and the chip
auto-runs all cycles, signaling AVALID when all 18 registers are ready.

Also: default gain 64x, fulltest uses readAllChannels() directly.

Co-authored-by: ladyada <limor@ladyada.net>

Author: clawpi

Adafruit_AS7343.cpp

@@ -307,6 +307,7 @@ bool Adafruit_AS7343::dataReady() {
  */
 bool Adafruit_AS7343::readAllChannels(uint16_t *readings_buffer) {
   setBank(false);
+
   // Determine how many channels based on mode
   as7343_smux_mode_t mode = getSMUXMode();
   uint8_t num_channels = 6;
@@ -316,15 +317,34 @@ bool Adafruit_AS7343::readAllChannels(uint16_t *readings_buffer) {
     num_channels = 18;
   }
 
-  // Read ASTATUS first to latch all data
+  // Start one measurement — auto-SMUX runs all cycles internally
+  if (!startMeasurement()) {
+    return false;
+  }
+
+  // Wait for AVALID (fires after all cycles complete)
+  uint32_t start = millis();
+  while (!dataReady()) {
+    if (millis() - start > 1000) {
+      return false;
+    }
+    delay(1);
+  }
+
+  // Read ASTATUS to latch data and clear AVALID
   Adafruit_BusIO_Register astatus_reg =
       Adafruit_BusIO_Register(i2c_dev, AS7343_ASTATUS);
   astatus_reg.read();
 
   // Read all data registers in one burst
+  // DATA_0_L starts at 0x96, each channel is 2 bytes (little-endian)
   Adafruit_BusIO_Register data_reg =
       Adafruit_BusIO_Register(i2c_dev, AS7343_DATA_0_L, 2);
-  return data_reg.read((uint8_t *)readings_buffer, num_channels * 2);
+  if (!data_reg.read((uint8_t *)readings_buffer, num_channels * 2)) {
+    return false;
+  }
+
+  return true;
 }
 
 /**

examples/fulltest/fulltest.ino

@@ -39,7 +39,7 @@ void setup() {
   // === Spectral Engine Configuration ===
   Serial.println(F("\n--- Spectral Configuration ---"));
 
-  as7343.setGain(AS7343_GAIN_256X);
+  as7343.setGain(AS7343_GAIN_64X);
   Serial.print(F("Gain: "));
   switch (as7343.getGain()) {
   case AS7343_GAIN_0_5X:
@@ -171,30 +171,12 @@ void setup() {
 void loop() {
   uint16_t readings[18];
 
-  // Start measurement
-  as7343.startMeasurement();
-
-  // Wait for data with timeout
-  uint32_t start = millis();
-  while (!as7343.dataReady()) {
-    if (millis() - start > 500) {
-      Serial.println(F("Timeout waiting for data!"));
-      return;
-    }
-    delay(1);
+  if (!as7343.readAllChannels(readings)) {
+    Serial.println(F("Read failed!"));
+    delay(500);
+    return;
   }
 
-  // Check saturation
-  if (as7343.isAnalogSaturated()) {
-    Serial.print(F("[ANALOG SAT] "));
-  }
-  if (as7343.isDigitalSaturated()) {
-    Serial.print(F("[DIGITAL SAT] "));
-  }
-
-  // Read all channels
-  as7343.readAllChannels(readings);
-
   // Print in wavelength order for easier reading
   Serial.print(F("F1:"));
   Serial.print(readings[AS7343_CHANNEL_F1]);
@@ -220,10 +202,7 @@ void loop() {
   Serial.print(F("\tF8:"));
   Serial.print(readings[AS7343_CHANNEL_F8]);
   Serial.print(F("\tNIR:"));
-  Serial.print(readings[AS7343_CHANNEL_NIR]);
-
-  Serial.print(F("\tVIS:"));
-  Serial.println(readings[AS7343_CHANNEL_VIS_TL_0]);
+  Serial.println(readings[AS7343_CHANNEL_NIR]);
 
   delay(100);
 }