Adjust sample rates & stereo mode

- Enable Stereo mode for NRF52840 - Set Stereo mode to MONO by default - Enable 24kHz sample rates for NRF52840
TMRh20 · Oct 18, 2024 · 26c71ac · 26c71ac
1 parent db738ef
commit 26c71ac
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Showing 2 changed files with 22 additions and 6 deletions.
diff --git a/src/AutoAnalogAudio.h b/src/AutoAnalogAudio.h
@@ -110,9 +110,9 @@ class AutoAnalog
 
   /** Set sample rate. 0 enables the default rate specified in AutoAnalog_config.h
    * @param sampRate This sets the defined sample rate ie: 32000 is 32Khz
-   * @param stereo Only used for the ESP32, this sets stereo or mono output and affects the sample rate
+   * @param stereo Only used for the ESP32 & NRF52840 this sets stereo or mono output and affects the sample rate
    */
-  void setSampleRate(uint32_t sampRate = 0, bool stereo = true);
+  void setSampleRate(uint32_t sampRate = 0, bool stereo = false);
 
   /** Function called by DAC IRQ */
   void dacHandler(void);

diff --git a/src/NRF52840/AutoAnalogAudio.cpp b/src/NRF52840/AutoAnalogAudio.cpp
@@ -338,15 +338,23 @@ void AutoAnalog::setSampleRate(uint32_t sampRate, bool stereo){
       }else
       if(dacBitsPerSample == 24){
         NRF_I2S->CONFIG.SWIDTH = I2S_CONFIG_SWIDTH_SWIDTH_24BIT << I2S_CONFIG_SWIDTH_SWIDTH_Pos;
-      } */          
-
+      } */
+
+      if(stereo){
+        NRF_I2S->CONFIG.CHANNELS = I2S_CONFIG_CHANNELS_CHANNELS_STEREO << I2S_CONFIG_CHANNELS_CHANNELS_Pos;
+      }
+
       if(sampRate <= 16000){
         NRF_I2S->CONFIG.MCKFREQ = I2S_CONFIG_MCKFREQ_MCKFREQ_32MDIV16 << I2S_CONFIG_MCKFREQ_MCKFREQ_Pos;
         NRF_I2S->CONFIG.RATIO = I2S_CONFIG_RATIO_RATIO_128X << I2S_CONFIG_RATIO_RATIO_Pos;
       }else
       if(sampRate <= 20000){
-        NRF_I2S->CONFIG.MCKFREQ = I2S_CONFIG_MCKFREQ_MCKFREQ_32MDIV8 << I2S_CONFIG_MCKFREQ_MCKFREQ_Pos;
-        NRF_I2S->CONFIG.RATIO = I2S_CONFIG_RATIO_RATIO_256X << I2S_CONFIG_RATIO_RATIO_Pos;
+        NRF_I2S->CONFIG.MCKFREQ = I2S_CONFIG_MCKFREQ_MCKFREQ_32MDIV15 << I2S_CONFIG_MCKFREQ_MCKFREQ_Pos;
+        NRF_I2S->CONFIG.RATIO = I2S_CONFIG_RATIO_RATIO_128X << I2S_CONFIG_RATIO_RATIO_Pos;
+      }else
+      if(sampRate <= 24000){
+        NRF_I2S->CONFIG.MCKFREQ = I2S_CONFIG_MCKFREQ_MCKFREQ_32MDIV11 << I2S_CONFIG_MCKFREQ_MCKFREQ_Pos;
+        NRF_I2S->CONFIG.RATIO = I2S_CONFIG_RATIO_RATIO_128X << I2S_CONFIG_RATIO_RATIO_Pos;
       }else
       if(sampRate <= 32000){
         NRF_I2S->CONFIG.MCKFREQ = I2S_CONFIG_MCKFREQ_MCKFREQ_32MDIV16 << I2S_CONFIG_MCKFREQ_MCKFREQ_Pos;
@@ -377,6 +385,14 @@ void AutoAnalog::setSampleRate(uint32_t sampRate, bool stereo){
          nrf_pdm_clock_set(myPDM,NRF_PDM_FREQ_1280K);
        #endif
     }else
+    if(sampRate <= 24000){
+      NRF_PDM->RATIO = ((PDM_RATIO_RATIO_Ratio80 << PDM_RATIO_RATIO_Pos) & PDM_RATIO_RATIO_Msk);
+      #if defined __MBED__
+        nrf_pdm_clock_set(NRF_PDM_FREQ_2000K);
+      #else
+        nrf_pdm_clock_set(myPDM, NRF_PDM_FREQ_2000K);       
+      #endif
+    }else
     if(sampRate <= 32000){
       NRF_PDM->RATIO = ((PDM_RATIO_RATIO_Ratio64 << PDM_RATIO_RATIO_Pos) & PDM_RATIO_RATIO_Msk);
       #if defined __MBED__