Multi-bit port support for Potentiometer mode

examples/pot_reader/src/main.xc

@@ -12,12 +12,13 @@
 #define FILTER_DEPTH        16
 #define HYSTERESIS          1
 
-on tile[1]: port p_adc[] = {XS1_PORT_1M, XS1_PORT_1O}; // Sets which pins are to be used (channels 0..n) X1D36/38
+// Select your port as required. Either 1b or wide ports may be used.
+// on tile[1]: port p_adc[] = {XS1_PORT_1M, XS1_PORT_1O}; // Sets which pins are to be used (channels 0..n) X1D36/38
+on tile[1]: port p_adc[] = {XS1_PORT_4A}; // Sets which pins are to be used (channels 0..n) X1D02/03
 
 
 void control_task(chanend ?c_adc, uint16_t * unsafe result_ptr){
     printf("Running QADC in continuous mode using dedicated task!\n");
-
     unsigned counter = 0;
 
     while(1){
@@ -91,17 +92,20 @@ int main() {
 
             const float v_rail = 3.3;
             const float v_thresh = 1.15;
-            const char auto_scale = 1;
+            const char auto_scale = 0;
 
+            const uint16_t port_time_offset = 36;      // 36 for 120MHz thread speed. Use 56 for 75MHz thread speed
             const unsigned convert_interval_ticks = (1 * XS1_TIMER_KHZ); // 1 millisecond
 
-            const qadc_config_t adc_config = {capacitor_pf,
+            const qadc_config_t adc_config = {  capacitor_pf,
                                                 potentiometer_ohms,
                                                 resistor_series_ohms,
                                                 v_rail,
                                                 v_thresh,
+                                                auto_scale,
                                                 convert_interval_ticks,
-                                                auto_scale};
+                                                port_time_offset};
+
             qadc_pot_state_t adc_pot_state;
 
             uint16_t state_buffer[QADC_POT_STATE_SIZE(NUM_ADC, LUT_SIZE, FILTER_DEPTH)];

examples/rheo_reader/src/main.xc

@@ -88,14 +88,16 @@ int main() {
             const char auto_scale = 0;
 
             const unsigned convert_interval_ticks = (1 * XS1_TIMER_KHZ);
-
+            const uint16_t port_time_offset = 32;      // 32 for 120MHz thread speed. Use 52 for 75MHz thread speed
+
             const qadc_config_t adc_config = {capacitor_pf,
                                                 potentiometer_ohms,
                                                 resistor_series_ohms,
                                                 v_rail,
                                                 v_thresh,
+                                                auto_scale,
                                                 convert_interval_ticks,
-                                                auto_scale};
+                                                port_time_offset};
 
             qadc_rheo_state_t adc_rheo_state;
             uint16_t state_buffer[QADC_RHEO_STATE_SIZE(NUM_ADC, FILTER_DEPTH)];

lib_qadc/api/qadc.h

@@ -34,11 +34,18 @@ typedef struct qadc_config_t{
     float v_thresh;
     /** The full conversion cycle time per channel (adc_xxx_task() only). The task will assert
      *  at initialisation if this is too short. */
+    char auto_scale;
+    /** Timing offset for the zero setting (rheostat) or end settings (potentiometer). 
+     *  This accounts for the minimum time measured by the QADC when the capacitor is already at
+     *  the expected value but the code takes a finite time to measure this.
+     * 
+     */
     unsigned convert_interval_ticks;
     /** Boolean setting which allows the end points of the QADC to be stretched if the read value
      *  exceeds the expected value. The new end point will be kept until the task is re-started. 
      *  This is ignored in single shot mode. */ 
-    char auto_scale;
+
+    uint16_t port_time_offset;
 }qadc_config_t;
 
 /**

lib_qadc/api/qadc_pot.h

@@ -10,6 +10,7 @@
  */
 typedef struct qadc_pot_state_t{
     size_t num_adc;
+    unsigned port_width;
     unsigned adc_idx;
     size_t lut_size;
     size_t filter_depth;
@@ -25,7 +26,6 @@ typedef struct qadc_pot_state_t{
     qadc_q3_13_fixed_t * UNSAFE max_scale_up;
     qadc_q3_13_fixed_t * UNSAFE max_scale_down;
     unsigned crossover_idx;
-    uint32_t port_time_offset;
     uint16_t * UNSAFE conversion_history;
     uint16_t * UNSAFE hysteris_tracker;
     uint16_t * UNSAFE init_port_val;

lib_qadc/api/qadc_rheo.h

@@ -20,7 +20,6 @@ typedef struct qadc_rheo_state_t{
     uint16_t * UNSAFE max_seen_ticks;
     qadc_q3_13_fixed_t * UNSAFE max_scale;
     unsigned crossover_idx;
-    uint16_t port_time_offset;
     uint16_t * UNSAFE conversion_history;
     uint16_t * UNSAFE hysteris_tracker;
     uint16_t * UNSAFE filter_write_idx;