Oscilliscope: Implement two, three, and four channel mode

pslab-core.X/commands.c

@@ -89,17 +89,17 @@ command_func_t* const cmd_table[NUM_PRIMARY_CMDS + 1][NUM_SECONDARY_CMDS_MAX + 1
     },
     { // 2 ADC
      // 0                          1 CAPTURE_ONE                2 CAPTURE_TWO                   3 CAPTURE_DMASPEED
-        Undefined,                 OSCILLOSCOPE_CaptureOne,     Unimplemented,                  Unimplemented,
+        Undefined,                 OSCILLOSCOPE_CaptureOne,     OSCILLOSCOPE_CaptureTwo,        Unimplemented,
      // 4 CAPTURE_FOUR             5 CONFIGURE_TRIGGER          6 GET_CAPTURE_STATUS            7 GET_CAPTURE_CHANNEL
-        Unimplemented,             Unimplemented,               OSCILLOSCOPE_GetCaptureStatus,  Unimplemented,
+        OSCILLOSCOPE_CaptureFour,  Unimplemented,               OSCILLOSCOPE_GetCaptureStatus,  Unimplemented,
      // 8 SET_PGA_GAIN             9 GET_VOLTAGE                10 GET_VOLTAGE_SUMMED           11 START_ADC_STREAMING
         Unimplemented,             MULTIMETER_GetVoltage,       MULTIMETER_GetVoltageSummed,    Removed,
      // 12 SELECT_PGA_CHANNEL      13 CAPTURE_12BIT             14 CAPTURE_MULTIPLE             15 SET_HI_CAPTURE
         Unimplemented,             Unimplemented,               Removed,                        Unimplemented,
      // 16 SET_LO_CAPTURE          17 SET_HI_CAPTURE12          18 SET_LO_CAPTURE12             19 CAPTURE_DMASPEED12
         Unimplemented,             Unimplemented,               Unimplemented,                  Unimplemented,
-     // 20 MULTIPOINT_CAPACITANCE  21 SET_CAP                   22 PULSE_TRAIN                  23
-        Unimplemented,             Unimplemented,               Unimplemented,                  Undefined,
+     // 20 MULTIPOINT_CAPACITANCE  21 SET_CAP                   22 PULSE_TRAIN                  23 CAPTURE_THREE
+        Unimplemented,             Unimplemented,               Unimplemented,                  OSCILLOSCOPE_CaptureThree,
      // 24                         25                           26                              27
         Undefined,                 Undefined,                   Undefined,                      Undefined,
     },

pslab-core.X/commands.h

@@ -19,7 +19,7 @@ extern "C" {
  */
 #define NUM_PRIMARY_CMDS 11
 #define NUM_FLASH_CMDS 4
-#define NUM_ADC_CMDS 22
+#define NUM_ADC_CMDS 23
 #define NUM_SPI_CMDS 7
 #define NUM_I2C_CMDS 16
 #define NUM_UART2_CMDS 8

pslab-core.X/instruments/oscilloscope.c

@@ -28,8 +28,9 @@ static uint16_t volatile SAMPLES_CAPTURED;
 static uint16_t SAMPLES_REQUESTED;
 
 /* Static function prototypes */
+static void Capture(void);
 static void ResetTrigger(void);
-static void Setup10BitMode(void);
+static void SetTimeGap(void);
 
 /**
  * @brief Handle trigger and data collection from ADC.
@@ -76,26 +77,70 @@ void __attribute__((interrupt, no_auto_psv)) _AD1Interrupt(void) {
 }
 
 response_t OSCILLOSCOPE_CaptureOne(void) {
-    uint8_t pin = UART1_Read();
+    CHANNELS = 0; // Capture one channel.
+    Capture();    
+    return SUCCESS;
+}
+
+response_t OSCILLOSCOPE_CaptureTwo(void) {
+    CHANNELS = 1; // Capture two channels.
+    Capture();
+    return SUCCESS;
+}
+
+response_t OSCILLOSCOPE_CaptureThree(void) {
+    CHANNELS = 2; // Capture four channels, but ignore the fourth.
+    Capture();
+    return SUCCESS;
+}
+
+response_t OSCILLOSCOPE_CaptureFour(void) {
+    CHANNELS = 3; // Capture four channels.
+    Capture();
+    return SUCCESS;
+}
+
+static void Capture(void) {
+    uint8_t config = UART1_Read();
     SAMPLES_REQUESTED = UART1_ReadInt();
     DELAY = UART1_ReadInt();
+    /*
+     * First channel input map:
+     *     CH1: 3,
+     *     CH2: 0,
+     *     CH3: 1,
+     *     MIC: 2,
+     *     RES: 7,
+     *     CAP: 5,
+     *     VOL: 8,
+     */
+    uint8_t ch0sa = config & 0x0F;
+    /* 
+     * Second, third, and fourth channels input map:
+     *     CH2, CH3, MIC: 0
+     *     CH1, CH2, CAP: 1
+     */
+    uint8_t ch123sa = config & 0x10;
+    uint8_t trigger = config & 0x80;
 
-    CHANNELS = 0; //capture one channel
-    AD1CON2bits.CHPS = 0;
-    ADC1_SetOperationMode(ADC1_10BIT_SIMULTANEOUS_MODE, pin & 0x7F, 0);
-    AD1CON2bits.CHPS = 0;
+    AD1CON2bits.CHPS = CHANNELS;
+    ADC1_SetOperationMode(ADC1_10BIT_SIMULTANEOUS_MODE, ch0sa, ch123sa);
+    AD1CON2bits.CHPS = CHANNELS;
 
-    if (pin & 0x80) ResetTrigger();
+    if (trigger) ResetTrigger();
     else TRIGGERED = 1;
 
+    int i;
+    for (i = 0; i <= CHANNELS; i++) {
+        BUFFER_IDX[i] = &BUFFER[i * SAMPLES_REQUESTED];
+    }
+
     SAMPLES_CAPTURED = 0;
     BUFFER_IDX[0] = &BUFFER[0];
-    Setup10BitMode();
+    SetTimeGap();
     ADC1_InterruptFlagClear();
     ADC1_InterruptEnable();
-    LED_SetLow();
-
-    return SUCCESS;
+    LED_SetLow();   
 }
 
 static void ResetTrigger(void) {
@@ -104,7 +149,7 @@ static void ResetTrigger(void) {
     TRIGGERED = 0;
 }
 
-static void Setup10BitMode(void) {
+static void SetTimeGap(void) {
     T5CONbits.TCKPS = 1;
     TMR5_Period16BitSet(DELAY - 1);
     TMR5 = 0;
@@ -113,7 +158,7 @@ static void Setup10BitMode(void) {
 
 response_t OSCILLOSCOPE_GetCaptureStatus(void) {
     uint8_t conversion_done;
-    conversion_done = SAMPLES_CAPTURED == SAMPLES_REQUESTED ? 1 : 0;
+    conversion_done = SAMPLES_CAPTURED == SAMPLES_REQUESTED;
     UART1_Write(conversion_done);
     UART1_WriteInt(SAMPLES_CAPTURED);
     return SUCCESS;

pslab-core.X/instruments/oscilloscope.h

@@ -6,14 +6,39 @@
  * 
  * @description
  * This command function takes three arguments over serial:
- * 1. (uint8) The pin to sample
- * 2. (uint16) The number of samples to capture
- * 3. (uint16) The time to wait between samples in instruction cycles
+ * 1. (uint8)  Configuration byte; The first four LSB encode channel one mapping,
+ *             the fifth LSB encodes channels two, three, and four mappings, and
+ *             the MSB enables the trigger.
+ * 2. (uint16) The number of samples to capture.
+ * 3. (uint16) The time to wait between samples in instruction cycles.
  * It returns nothing over serial.
  * It sends an acknowledge byte (SUCCESS).
+ * 
+ * @return SUCCESS
  */
 response_t OSCILLOSCOPE_CaptureOne(void);
 
+/**
+ * @brief Capture samples on two channels simultaneously.
+ */
+response_t OSCILLOSCOPE_CaptureTwo(void);
+
+/**
+ * @brief Capture samples on three channels simultaneously.
+ * 
+ * @description
+ * Since the MCU only supports 1, 2, or 4 simultaneous channels, this is
+ * accomplished by sampling four channels simultaneously and discarding the
+ * samples from the fourth. This function therefore has the same sample rate
+ * as OSCILLOSCOPE_CaptureFour, but greater sample depth.
+ */
+response_t OSCILLOSCOPE_CaptureThree(void);
+
+/**
+ * @brief Capture samples on four channels simultaneously.
+ */
+response_t OSCILLOSCOPE_CaptureFour(void);
+
 /**
  * @brief
  * Send capture progress.