From 0cb345ed5ccbe786d0a7e7e2de740c0a07b82770 Mon Sep 17 00:00:00 2001
From: ozpv <39195175+ozpv@users.noreply.github.com>
Date: Wed, 19 Aug 2026 21:34:09 -0500
Subject: sdram and ringmod effect

---
 Core/Src/cs4272.c | 122 ++++++++++++++++++++++++++++++------------------------
 1 file changed, 69 insertions(+), 53 deletions(-)

(limited to 'Core/Src/cs4272.c')

diff --git a/Core/Src/cs4272.c b/Core/Src/cs4272.c
index e7b639e..81179c7 100755
--- a/Core/Src/cs4272.c
+++ b/Core/Src/cs4272.c
@@ -7,42 +7,78 @@
 
 #include "i2c.h"
 #include "cs4272.h"
+#include "ringmod.h"
 
 volatile int32_t rx_buffer[BUFFER_SIZE] __attribute__((section(".audio_buffers")));
 volatile int32_t tx_buffer[BUFFER_SIZE] __attribute__((section(".audio_buffers")));
+volatile float samples[BUFFER_SIZE] __attribute__((section(".sdram")));
 
 const uint8_t CS4272_CONFIG[7] = {
-        // MODE CONTROL 1
-        // single speed i2s slave
+        /* MODE CONTROL 1
+           single speed i2s slave */
         0b00000001,
-        // DAC CONTROL
-        // no auto mute steep roll off interpolation 48 kHz de-emphasis
-        // Soft Ramp Up and Down and no polarity flipping
-        0b00001100,
-        // DAC Volume & Mixing Control
-        // Channel B Volume = Channel A Volume Soft Ramp and Zero Cross
-        // a = L b = R
-        0b01111001,
-        // Channel A volume
-        // 0 dB
-        // Binary Code Decimal Value Volume Setting
-        // 0000000 0 0 dB
-        // 0010100 20 -20 dB
-        // 0101000 40 -40 dB
-        // 0111100 60 -60 dB
-        // 1011010 90 -90 dB
+        /* DAC CONTROL
+          Steep Interpolation Filter
+          48 kHz de-emphasis
+          Soft Ramp Up and Down and no polarity flip */
+        0b01101100,
+        /* DAC Volume & Mixing Control
+          Channel B Volume = Channel A Volume
+          Soft Ramp and Zero Cross
+          a = L b = R
+          stereo 0b01111001 */
+        0b01111000,
+        /* Channel A volume
+           0 dB
+           Binary Code Decimal Value Volume Setting
+           0000000 0 0 dB
+           0010100 20 -20 dB
+           0101000 40 -40 dB
+           0111100 60 -60 dB
+           1011010 90 -90 dB */
         0b00000000,
-        // Channel B volume
-        0b00000000,
-        // ADC control
-        // I2S up to 24-bit data High Pass filter on
-        // bits 3:2 adc channel mute
-        0b00010000,
-        // MODE CONTROL 2
-        // power down OFF
+        /* Channel B volume
+           Muted for mono */
+        0b10000000,
+        /* ADC control
+           I2S up to 24-bit data High Pass filter on
+           bits 3:2 active high adc channel mute
+           Channel B muted */
+        0b00010100,
+        /* MODE CONTROL 2
+           power down OFF */
         0b00000010,
 };
 
+void int32_t_to_float(int32_t *in, float *out, size_t range_min, size_t range_max) {
+    for (size_t i = range_min; i < range_max; ++i) {
+        out[i] = ((float)(in[i] << 8)) / ((float)INT32_MAX);
+    }
+}
+
+void float_to_int32_t(float *in, int32_t *out, size_t range_min, size_t range_max) {
+    for (size_t i = range_min; i < range_max; ++i) {
+        out[i] = ((int32_t)(in[i] * ((float)INT32_MAX))) >> 8;
+    }
+}
+
+void HAL_SAI_RxHalfCpltCallback(SAI_HandleTypeDef *hsai) {
+    int32_t_to_float((int32_t *)rx_buffer, (float *)samples, 0, BUFFER_SIZE / 2);
+
+    ringmod((float *)samples, 0, BUFFER_SIZE / 2);
+
+    float_to_int32_t((float *)samples, (int32_t *)tx_buffer, 0, BUFFER_SIZE / 2);
+}
+
+void HAL_SAI_RxCpltCallback(SAI_HandleTypeDef *hsai) {
+    int32_t_to_float((int32_t *)rx_buffer, (float *)samples, BUFFER_SIZE / 2, BUFFER_SIZE);
+
+    ringmod((float *)samples, BUFFER_SIZE / 2, BUFFER_SIZE);
+
+    float_to_int32_t((float *)samples, (int32_t *)tx_buffer, BUFFER_SIZE / 2, BUFFER_SIZE);
+}
+
+
 HAL_StatusTypeDef CS4272_ReadRegister(uint8_t addr, uint8_t *data) {
     return HAL_I2C_Mem_Read(&hi2c4, CS4272_I2C_ADDR, addr, I2C_MEMADD_SIZE_8BIT,
             data, 1, HAL_MAX_DELAY);
@@ -53,7 +89,7 @@ HAL_StatusTypeDef CS4272_WriteRegister(uint8_t addr, uint8_t data) {
     I2C_MEMADD_SIZE_8BIT, &data, 1, HAL_MAX_DELAY);
 }
 
-void CS4272_Reset() {
+void CS4272_Reset(void) {
     HAL_GPIO_WritePin(GPIOB, GPIO_PIN_7, GPIO_PIN_RESET);
 
     HAL_Delay(10);
@@ -63,20 +99,20 @@ void CS4272_Reset() {
     HAL_Delay(10);
 }
 
-uint8_t CS4272_Init() {
+uint8_t CS4272_Init(void) {
     CS4272_Reset();
 
     if (HAL_I2C_IsDeviceReady(&hi2c4, CS4272_I2C_ADDR, 3, 1000) != HAL_OK) {
         return HAL_ERROR;
     }
 
-    // 5.2.1 Recommended Power-Up Sequence
-    // power down mode and control port enable
+    /* 5.2.1 Recommended Power-Up Sequence
+       power down mode and control port enable */
     if (CS4272_WriteRegister(MODE_CONTROL_2, 0x03) != HAL_OK) {
         return HAL_ERROR;
     }
 
-    // check if device ID is correct
+    /* check if device ID is correct */
     uint8_t id = 0;
     if (CS4272_ReadRegister(CHIP_ID, &id) != HAL_OK) {
         return HAL_ERROR;
@@ -86,9 +122,9 @@ uint8_t CS4272_Init() {
         return 2;
     }
 
-    // Configure
+    /* Configure */
     uint8_t cfg = 0;
-    for (uint8_t i = MODE_CONTROL_1; i < MODE_CONTROL_2; ++i) {
+    for (size_t i = MODE_CONTROL_1; i < CHIP_ID; ++i) {
         if (CS4272_WriteRegister(i, CS4272_CONFIG[i - 1]) != HAL_OK) {
             return HAL_ERROR;
         }
@@ -102,25 +138,5 @@ uint8_t CS4272_Init() {
         }
     }
 
-    if (CS4272_WriteRegister(MODE_CONTROL_2, 0x02) != HAL_OK) {
-        return HAL_ERROR;
-    }
-
-    if (CS4272_ReadRegister(MODE_CONTROL_2, &cfg) != HAL_OK || cfg != 0x02) {
-        return 2;
-    }
-
     return HAL_OK;
 }
-
-void HAL_SAI_RxHalfCpltCallback(SAI_HandleTypeDef *hsai) {
-    for(int i = 0; i < BUFFER_SIZE / 2; i++) {
-        tx_buffer[i] = rx_buffer[i];
-    }
-}
-
-void HAL_SAI_RxCpltCallback(SAI_HandleTypeDef *hsai) {
-    for(int i = BUFFER_SIZE / 2; i < BUFFER_SIZE; i++) {
-        tx_buffer[i] = rx_buffer[i];
-    }
-}
-- 
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