varpa: initial public commit

1 files changed, 152 insertions, 0 deletions

diff --git a/firmware/src/util.c b/firmware/src/util.c
new file mode 100644
index 0000000..af6ffed
--- /dev/null
+++ b/firmware/src/util.c
@@ -0,0 +1,152 @@
+/**
+ * 
+ * Author: Dylan Muller
+ * Copyright (c) 2025 
+ * All rights reserved.
+ * 
+ * - Commercial/IP use prohibited.
+ * - Attribution required.
+ * See License.txt
+ *
+ */
+
+#include "util.h"
+
+#include <stdio.h>
+#include <avr/pgmspace.h>
+
+extern int __heap_start, *__brkval;
+
+const uint16_t fw_pwr_gradient[] = { 249, 356, 374, 388, 400, 402, 435, 460, 500, 553 };
+const int16_t fw_pwr_intercept[] = { -5418, -3810, -3602, -3431, -3289, -3261, -2877, -2601, -2189, -1725 };
+const uint16_t fw_pwr_threshold[] = { 1288, 1548, 1704, 1812, 1897, 1967, 2164, 2301, 2411, 2505 };
+
+uint8_t util_volt_to_count(
+    uint16_t volt,
+    uint16_t* count
+)
+{
+    uint8_t bits = 0x0;
+    uint32_t x = 0x0;
+    uint32_t y = 0x0;
+    uint16_t i = 0x0;
+
+    bits = UTIL_CONV_BITS;
+
+    if (volt > UTIL_SYSTEM_VOLT)
+    {
+        return 1;
+    }
+
+    for (i = 0; i < bits; i++)
+    {
+        x |= UTIL_CONV_BIT(i);
+    }
+
+    y = ((uint32_t)volt) * x;
+    y /= UTIL_SYSTEM_VOLT;
+
+    *count = (uint16_t)y;
+    return 0;
+}
+
+uint8_t util_count_to_volt(
+    uint16_t count,
+    uint16_t* volt
+)
+{
+    uint8_t bits = 0x0;
+    uint32_t x = 0x0;
+    uint32_t y = 0x0;
+    uint16_t i = 0x0;
+
+    bits = UTIL_CONV_BITS;
+
+    for (i = 0; i < bits; i++)
+    {
+        x |= UTIL_CONV_BIT(i);
+    }
+
+    if (count > x)
+    {
+        return 1;
+    }
+
+    y = ((uint32_t)count) * UTIL_SYSTEM_VOLT;
+    y /= x;
+
+    *volt = (uint16_t)y;
+    return 0;
+}
+
+int8_t util_count_to_pwr(
+    uint16_t count,
+    int16_t* cpwr
+)
+{
+    uint32_t x = 0x0;
+    int16_t y = 0x0;
+    uint16_t slope = 0x0;
+    int16_t intercept = 0x0;
+    uint16_t i = 0;
+
+    uint8_t pwr_cal_size = sizeof(fw_pwr_gradient) / sizeof(uint16_t);
+    uint8_t pwr_last_element = pwr_cal_size - 1;
+
+    if(count >= fw_pwr_threshold[pwr_last_element])
+    {
+        slope = fw_pwr_gradient[pwr_last_element];
+        intercept = fw_pwr_intercept[pwr_last_element];
+    }
+    else if (count <= fw_pwr_threshold[0])
+    {
+        slope = fw_pwr_gradient[0];
+        intercept = fw_pwr_intercept[0];
+    }
+    else
+    {
+        for(i = 0; i < pwr_cal_size; i++)
+        {
+            if(count < fw_pwr_threshold[i])
+            {
+                slope = fw_pwr_gradient[i];
+                intercept = fw_pwr_intercept[i];
+                break;
+            }
+        }
+    }
+
+    x = (((uint32_t)count * 1000) / slope);
+    y = (int16_t)x;
+
+    y = y + intercept;
+    *cpwr = y;
+
+    return 0;
+}
+
+void util_print_pwr(
+    int16_t cpwr
+)
+{
+    int16_t integer_part = cpwr / 100;
+    
+    int16_t fractional_part = cpwr % 100;
+
+    if (fractional_part < 0) {
+        fractional_part = -fractional_part;
+    }
+
+    printf("%d.%02d dBm\n", integer_part, fractional_part);
+}
+
+uint16_t util_get_free_mem(void)
+{
+    uint16_t free_mem;
+    if ((int)__brkval == 0) {
+        free_mem = (int)&free_mem - (int)&__heap_start;
+    } else {
+        free_mem = (int)&free_mem - (int)__brkval;
+    }
+    return free_mem;
+}