Add JM science scale support

src/html/web_portal.html

@@ -111,6 +111,7 @@
                                     <option value="1">Steinberg SBS</option>
                                     <option value="2">GNG JJB</option>
                                     <option value="3">US Solid JFDBS</option>
+                                    <option value="4">JM Science</option>
                                 </select>
                             </div>
 

src/jm_science_scale.c

@@ -0,0 +1,109 @@
+#include <FreeRTOS.h>
+#include <queue.h>
+#include <stdlib.h>
+#include <semphr.h>
+#include <time.h>
+#include <math.h>
+#include <task.h>
+#include <stdlib.h>
+
+#include "hardware/uart.h"
+#include "configuration.h"
+#include "scale.h"
+#include "app.h"
+
+
+typedef union {
+    struct __attribute__((__packed__)){
+        char header;
+        char _space;
+        char stable_state;
+        char symbol;
+        char weighing_data[9];
+        char _space2;
+        char weighing_unit[3];
+        char terminator[2];
+    };
+    char bytes[19];
+} jm_science_frame_data_format_t;
+
+
+const static char JM_SCIENCE_FRAME_HEADER = 'E';
+
+
+// Forward declaration
+void _jm_science_scale_listener_task(void *p);
+static void force_zero();
+
+extern scale_config_t scale_config;
+
+// Instance of the scale handle for JM Sciense FA series
+scale_handle_t jm_science_scale_handle = {
+    .read_loop_task = _jm_science_scale_listener_task,
+    .force_zero = force_zero,
+};
+
+
+static float _decode_measurement_msg(jm_science_frame_data_format_t * frame) {
+    // decode sign 
+    int sign = 1;
+    if (frame->symbol == '-') {
+        sign = -1;
+    }
+
+    // Decode weight information
+    char *endptr;
+    float weight = strtof(frame->weighing_data, &endptr);
+
+    if( endptr == frame->weighing_data ) {
+        // Conversion failed
+        return nanf(frame->weighing_data);
+    }
+
+    weight *= sign;
+
+    return weight;
+}
+
+
+void _jm_science_scale_listener_task(void *p) {
+    jm_science_frame_data_format_t frame;
+    uint8_t byte_idx = 0;
+
+    while (true) {
+        // Read all data 
+        while (uart_is_readable(SCALE_UART)) {
+            char ch = uart_getc(SCALE_UART);
+
+            // Determine if the frame header is received
+            // If a header is received then we should reset the decode sequence
+            if (ch == JM_SCIENCE_FRAME_HEADER) {
+                byte_idx = 0;
+            }
+
+            frame.bytes[byte_idx++] = ch;
+
+            // If we have received 17 bytes then we can decode the message
+            if (byte_idx == sizeof(jm_science_frame_data_format_t)) {
+                // Data is ready, send to decode
+                scale_config.current_scale_measurement = _decode_measurement_msg(&frame);
+
+                // Signal the data is ready
+                if (scale_config.scale_measurement_ready) {
+                    xSemaphoreGive(scale_config.scale_measurement_ready);
+                }
+
+                // Reset buffer index to avoid overflow
+                byte_idx = 0;
+            }
+        }
+
+        vTaskDelay(pdMS_TO_TICKS(20));
+    }
+}
+
+
+static void force_zero() {
+    // Unsupported
+}
+

src/scale.c

@@ -16,6 +16,8 @@ extern scale_handle_t and_fxi_scale_handle;
 extern scale_handle_t steinberg_scale_handle;
 extern scale_handle_t ussolid_scale_handle;
 extern scale_handle_t gng_scale_handle;
+extern scale_handle_t jm_science_scale_handle;
+
 scale_config_t scale_config;
 
 
@@ -35,14 +37,19 @@ void set_scale_driver(scale_driver_t scale_driver) {
             scale_config.scale_handle = &steinberg_scale_handle;
             break;
         }
+        case SCALE_DRIVER_GNG_JJB:
+        {
+            scale_config.scale_handle = &gng_scale_handle;
+            break;
+        }
         case SCALE_DRIVER_USSOLID_JFDBS:
         {
             scale_config.scale_handle = &ussolid_scale_handle;
             break;
         }
-         case SCALE_DRIVER_GNG_JJB:
+        case SCALE_DRIVER_JM_SCIENCE:
         {
-            scale_config.scale_handle = &gng_scale_handle;
+            scale_config.scale_handle = &jm_science_scale_handle;
             break;
         }
         default:
@@ -88,6 +95,8 @@ const char * get_scale_driver_string() {
         case SCALE_DRIVER_GNG_JJB:
             scale_driver_string = "GNG JJB";
             break;
+        case SCALE_DRIVER_JM_SCIENCE:
+            scale_driver_string = "JM SCIENCE";
         default:
             break;
     }

src/scale.h

@@ -31,6 +31,7 @@ typedef enum {
     SCALE_DRIVER_STEINBERG_SBS = 1,
     SCALE_DRIVER_GNG_JJB = 2,
     SCALE_DRIVER_USSOLID_JFDBS = 3,
+    SCALE_DRIVER_JM_SCIENCE = 4,
 } scale_driver_t;