initial work to get I2C digipot control working (#2)

DWT_delay.cpp

@@ -0,0 +1,92 @@
+/**
+* Digital Voice Modem - DSP Firmware
+* GPLv2 Open Source. Use is subject to license terms.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* @package DVM / DSP Firmware
+*
+*/
+//
+// Based on code from Mark Carter (https://mcturra2000.wordpress.com/2022/03/10/sending-data-over-i2c-using-bit-banging/)
+// And also https://github.com/PascalPolygon/stm32_bitbang_i2c/
+// Licensed under the GPLv2 License (https://opensource.org/licenses/GPL-2.0)
+//
+/*
+*   Copyright (C) 2023 by Patrick McDonnell, W3AXL
+*
+*   This library is free software; you can redistribute it and/or
+*   modify it under the terms of the GNU Library General Public
+*   License as published by the Free Software Foundation; either
+*   version 2 of the License, or (at your option) any later version.
+*
+*   This library is distributed in the hope that it will be useful,
+*   but WITHOUT ANY WARRANTY; without even the implied warranty of
+*   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+*   Library General Public License for more details.
+*
+*   You should have received a copy of the GNU Library General Public
+*   License along with this library; if not, write to the
+*   Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+*   Boston, MA  02110-1301, USA.
+*
+*/
+
+#include "DWT_delay.h"
+
+RCC_ClocksTypeDef RCC_Clocks;
+uint32_t HCLK_Freq;
+
+/**
+ * @brief  Initializes DWT_Clock_Cycle_Count for DWT_Delay_us function
+ * @return Error DWT counter
+ *         1: clock cycle counter not started
+ *         0: clock cycle counter works
+ */
+uint32_t DWT_Delay_Init(void) {
+    // Get HCLK for calculation (done here so we don't have to do it every time)
+    RCC_GetClocksFreq(&RCC_Clocks);
+    HCLK_Freq = RCC_Clocks.HCLK_Frequency;
+    /* Disable TRC */
+    CoreDebug->DEMCR &= ~CoreDebug_DEMCR_TRCENA_Msk; // ~0x01000000;
+    /* Enable TRC */
+    CoreDebug->DEMCR |=  CoreDebug_DEMCR_TRCENA_Msk; // 0x01000000;
+
+    /* Disable clock cycle counter */
+    DWT->CTRL &= ~DWT_CTRL_CYCCNTENA_Msk; //~0x00000001;
+    /* Enable  clock cycle counter */
+    DWT->CTRL |=  DWT_CTRL_CYCCNTENA_Msk; //0x00000001;
+
+    /* Reset the clock cycle counter value */
+    DWT->CYCCNT = 0;
+        /* 3 NO OPERATION instructions */
+        __ASM volatile ("NOP");
+        __ASM volatile ("NOP");
+        __ASM volatile ("NOP");
+
+    /* Check if clock cycle counter has started */
+        if(DWT->CYCCNT)
+        {
+        return 0; /*clock cycle counter started*/
+        }
+        else
+    {
+        return 1; /*clock cycle counter not started*/
+    }
+}
+
+/**
+ * @brief  This function provides a delay (in microseconds)
+ * @param  microseconds: delay in microseconds
+ */
+void DWT_Delay_us(volatile uint32_t microseconds)
+{
+  uint32_t clk_cycle_start = DWT->CYCCNT;
+
+  /* Go to number of cycles for system */
+  microseconds *= (HCLK_Freq / 1000000);
+
+  /* Delay till end */
+  while ((DWT->CYCCNT - clk_cycle_start) < microseconds);
+}
+
+/* Use DWT_Delay_Init (); and DWT_Delay_us (microseconds) in the main */

DWT_delay.h

@@ -0,0 +1,42 @@
+/**
+* Digital Voice Modem - DSP Firmware
+* GPLv2 Open Source. Use is subject to license terms.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* @package DVM / DSP Firmware
+*
+*/
+//
+// Based on code from Mark Carter (https://mcturra2000.wordpress.com/2022/03/10/sending-data-over-i2c-using-bit-banging/)
+// And also https://github.com/PascalPolygon/stm32_bitbang_i2c/
+// Licensed under the GPLv2 License (https://opensource.org/licenses/GPL-2.0)
+//
+/*
+*   Copyright (C) 2023 by Patrick McDonnell, W3AXL
+*
+*   This library is free software; you can redistribute it and/or
+*   modify it under the terms of the GNU Library General Public
+*   License as published by the Free Software Foundation; either
+*   version 2 of the License, or (at your option) any later version.
+*
+*   This library is distributed in the hope that it will be useful,
+*   but WITHOUT ANY WARRANTY; without even the implied warranty of
+*   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+*   Library General Public License for more details.
+*
+*   You should have received a copy of the GNU Library General Public
+*   License along with this library; if not, write to the
+*   Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+*   Boston, MA  02110-1301, USA.
+*
+*/
+
+#ifndef __DWT_DELAY_H__
+#define __DWT_DELAY_H__
+
+#include "stm32f4xx_rcc.h"
+
+uint32_t DWT_Delay_Init(void);
+void DWT_Delay_us(volatile uint32_t microseconds);
+
+#endif

Digipot.cpp

@@ -36,9 +36,7 @@
 Digipot::Digipot() :
     m_RxFine(127U),
     m_RxCoarse(127U),
-    m_TxFine(127U),
     m_TxCoarse(127U),
-    m_RssiFine(127U),
     m_RssiCoarse(127U)
 {
     /* stub */
@@ -48,47 +46,49 @@ void Digipot::initialize() {
     // reset all values to middle
     m_RxFine     = 127U;
     m_RxCoarse   = 127U;
-    m_TxFine     = 127U;
     m_TxCoarse   = 127U;
-    m_RssiFine   = 127U;
     m_RssiCoarse = 127U;
+
+    // Set the pot's ACR registers to non-volatile, non-shutdown mode
+    setRegister(TxPotAddr, TPL0102_REG_ACR, 0x40);
+    setRegister(RxPotAddr, TPL0102_REG_ACR, 0x40);
 
     // push the values to the pots
-    setPotVal(RxPotAddr, 0, m_RxFine);
-    setPotVal(RxPotAddr, 1, m_RxCoarse);
-    setPotVal(TxPotAddr, 0, m_TxFine);
-    setPotVal(TxPotAddr, 1, m_TxCoarse);
-    setPotVal(RssiPotAddr, 0, m_RssiFine);
-    setPotVal(RssiPotAddr, 1, m_RssiCoarse);
+    setRxFine(m_RxFine);
+    setRxCoarse(m_RxCoarse);
+    setTxCoarse(m_TxCoarse);
+    setRssiCoarse(m_RssiCoarse);
 }
 
-void Digipot::setPotVal(uint8_t addr, uint8_t reg, uint8_t value) {
-    uint8_t cmd[2U];
-    io.I2C_Write(addr, cmd, 2U);
+void Digipot::setRegister(uint8_t i2c_addr, uint8_t reg_addr, uint8_t reg_value) {
+    uint8_t cmd[2] = {reg_addr, reg_value};
+    io.I2C_Write(i2c_addr, cmd, 2U);
 }
 
 void Digipot::setRxFine(uint8_t val) {
-    setPotVal(RxPotAddr, 1, val);
+    setRegister(RxPotAddr, TPL0102_REG_WRB, val);
 }
 
 void Digipot::setRxCoarse(uint8_t val) {
-    setPotVal(RxPotAddr, 0, val);
+    setRegister(RxPotAddr, TPL0102_REG_WRA, val);
 }
 
 void Digipot::setTxFine(uint8_t val) {
-    setPotVal(TxPotAddr, 1, val);
+    //there is no TX fine pot so ignore this
+    return;
 }
 
 void Digipot::setTxCoarse(uint8_t val) {
-    setPotVal(TxPotAddr, 0, val);
+    setRegister(TxPotAddr, TPL0102_REG_WRA, val);
 }
 
 void Digipot::setRssiFine(uint8_t val) {
-    setPotVal(RssiPotAddr, 1, val);
+    //there is no RSSI fine pot so ignore this
+    return;
 }
 
 void Digipot::setRssiCoarse(uint8_t val) {
-    setPotVal(RssiPotAddr, 0, val);
+    setRegister(TxPotAddr, TPL0102_REG_WRB, val);
 }
 
 #endif // DIGIPOT_ENABLED

Digipot.h

@@ -9,7 +9,7 @@
 // Licensed under the GPLv2 License (https://opensource.org/licenses/GPL-2.0)
 //
 /*
-*   Copyright (C) 2022 by Natalie Moore
+*   Copyright (C) 2023 by Natalie Moore, Patrick McDonnell
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
@@ -25,6 +25,7 @@
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
+
 #if !defined(__DIGIPOT_H__)
 #define __DIGIPOT_H__
 
@@ -33,13 +34,13 @@
 #include "Defines.h"
 #include <stm32f4xx_i2c.h>
 
-#define RxPotAddr   0x2C
-#define TxPotAddr   0x2E
-#define RssiPotAddr 0x2F
+#define TxPotAddr   0xA2    // 7-Bit address 1010001 (0x51) becomes 0xA2 after << 1
+#define RxPotAddr   0xA4    // 7-Bit address 1010010 (0x52) becomes 0xA4 after << 1
+//#define RssiPotAddr 0x2E  // RSSI pot is part of TX pot IC
 
-#define AD5242_CMD_SET_RDAC1    0x00
-#define AD5242_CMD_SET_RDAC2    0x80
-#define AD5242_CMD_RESET        0x40
+#define TPL0102_REG_WRA     0x00
+#define TPL0102_REG_WRB     0x01
+#define TPL0102_REG_ACR     0x10
 
 // ---------------------------------------------------------------------------
 //  Class Declaration
@@ -75,12 +76,10 @@ class DSP_FW_API Digipot {
 private:
     uint8_t m_RxFine;
     uint8_t m_RxCoarse;
-    uint8_t m_TxFine;
     uint8_t m_TxCoarse;
-    uint8_t m_RssiFine;
     uint8_t m_RssiCoarse;
-    // helper to set softpot value at given address and register
-    void setPotVal(uint8_t addr, uint8_t reg, uint8_t value);
+    // helper to set registers
+    void setRegister(uint8_t i2c_addr, uint8_t reg_addr, uint8_t reg_value);
 };
 
 #endif // DIGIPOT_ENABLED

FirmwareMain.cpp

@@ -140,7 +140,7 @@ void setup()
 {
     serial.start();
 #if defined(DIGIPOT_ENABLED)
-    digitpot.initialize();
+    digipot.initialize();
 #endif
 }
 

Globals.h

@@ -139,7 +139,7 @@ extern CWIdTX cwIdTX;
 
 #if defined(DIGIPOT_ENABLED)
 /** Digipot */
-extern Digipot digitpot;
+extern Digipot digipot;
 #endif
 
 #if defined(NATIVE_SDR)