#20 WIP

LED_Matrix/lib/Serial/serial_uart/wip.cpp

@@ -2,26 +2,54 @@
 #include <stdint.h>
 #include <algorithm>
 
+const uint8_t header_checksum[1][4] = { {0} };
+
 // Preamble must be half of packet
 struct Packet {
     uint8_t preamble[32];
-    uint8_t inverse[16];
-    uint32_t length;
-    uint32_t command;
-    uint32_t marker;
-    uint32_t checksum;
+    uint8_t inverse[12];
+    uint8_t length[4];
+    uint8_t command[4];
+    uint8_t marker[4];
+    uint8_t header_checksum[4];
+    uint8_t payload_checksum[4];
 };
 
 static uint16_t index = 0;
+constexpr uint8_t command_count = 1;
+const uint8_t marker[4] = { 0x11, 0x19, 0x19, 0x90 };
+extern const uint8_t header_checksum[command_count][4];
 
 //uint8_t iterator(Packet *p1, Packet *p2, uint16_t i);
 
 void __attribute__ ((noinline)) other_task();
 void __attribute__ ((noinline)) task();
 
+constexpr uint8_t rows = 3;
+constexpr uint8_t columns = 16;
+volatile bool isReady = false;
+
+// Test misalignment (simulates errors in stream as seen by receiver)
+typedef Packet my_name[columns][rows];
+#define MISALIGN
+#ifdef MISALIGN
+Packet array2[columns*2][rows];
+uint8_t *vector = (uint8_t *) &array2[0][0].preamble[0];
+my_name *array;
+#else
+my_name array2;
+my_name *array;// = &array2;
+#endif
+
 int main(int argc, char **argv) {
     int LED_PIN = 0;
 
+#ifdef MISALIGN
+    array = (my_name *) &vector[15];
+#else
+    array = &array2;
+#endif
+
     gpio_init(LED_PIN);
     gpio_set_dir(LED_PIN, GPIO_OUT);
 
@@ -49,7 +77,8 @@ constexpr uint8_t iterator(Packet *p1, Packet *p2, uint16_t i) {
 }
 
 bool search(Packet *p1, Packet *p2) {
-    int i, j;
+    int i, j, k;
+    uint32_t c;
 
     // Look for start of preamble
     for (i = std::max(index - 4, 0); i < std::min(index, (uint16_t) 4); i++) {
@@ -63,9 +92,33 @@ bool search(Packet *p1, Packet *p2) {
             return false;
     }
 
-    j += 4;
+    // Verify Inverse
+    for (k = j; k < (int) (j + sizeof(Packet::inverse)); k++) {
+        if (iterator(p1, p2, k) != ~0x19)
+            return false;
+    }
+    j = k;
+
+    // TODO: Extract command and length
+    c %= command_count;
+    j += 8;
+
+    // Verify Marker
+    for (k = j; k < (int) (j + sizeof(Packet::marker)); k++) {
+        if (iterator(p1, p2, k) != marker[k - j])
+            return false;
+    }
+    j = k;
+
+    // Verify header checksum (hard coded by compiler for each command)
+    //  Length is a hard coded by compiler (this is factored into the checksum)
+    for (k = j; k < (int) (j + sizeof(Packet::header_checksum)); k++) {
+        if (iterator(p1, p2, k) != header_checksum[c][k - j])
+            return false;
+    }
+    j = k;
 
-    // TODO: Verify checksum, inverse, marker
+    // TODO: Extract payload checksum
 
     // Stay in phase or realign phase
     index = i;
@@ -83,21 +136,15 @@ bool isNewFrame(Packet *p1, Packet *p2) {
             break;
         }
 
-        // Spot check for preamble (fast reject/jump out)
         if (*(ptr + index) == 0x19)
             return search(p1, p2);
         else
-            index += sizeof(Packet) / 4;
+            index++;
     }
 
     return false;
 }
 
-constexpr uint8_t rows = 3;
-constexpr uint8_t columns = 16;
-Packet array[columns][rows];
-volatile bool isReady = false;
-
 void reset_state_machine() {
     // TODO    
 }
@@ -115,20 +162,20 @@ void task() {
 
     if (isReady) {
         // Handle boundary between rows
-        if (isNewFrame(&array[columns - 1][last], &array[0][(last + 1) % rows])) 
+        if (isNewFrame(array[columns - 1][last], array[0][(last + 1) % rows])) 
             reset_state_machine();
-        state_machine(&array[columns - 1][last]);
+        state_machine(array[columns - 1][last]);
 
         // Advance to next row
         last = (last + 1) % rows;
         isReady = false;
 
         // Handle columns in row
         for (int i = 0; i < (columns - 1); i++) {
-            if (isNewFrame(&array[i][last], &array[i + 1][last])) 
+            if (isNewFrame(array[i][last], array[i + 1][last])) 
                 reset_state_machine();
 
-            state_machine(&array[i][last]);
+            state_machine(array[i][last]);
         }
 
         flush_state_machine();
@@ -139,8 +186,28 @@ void other_task() {
     static uint8_t num = 0;
 
     for (int i = 0; i < columns; i++) {
+        for (int j = 0; j < (int) sizeof(Packet::command); j++) {
+            array[i][num]->command[j] = 0;
+        }
+
+        for (int j = 0; j < (int) sizeof(Packet::length); j++) {
+            array[i][num]->length[j] = (4096 >> (j * 8)) & 0xFF;
+        }
+
         for (int j = 0; j < (int) sizeof(Packet::preamble); j++) {
-            array[i][num].preamble[j] = 0x19;
+            array[i][num]->preamble[j] = 0x19;
+        }
+
+        for (int j = 0; j < (int) sizeof(Packet::inverse); j++) {
+            array[i][num]->inverse[j] = ~0x19;
+        }
+
+        for (int j = 0; j < (int) sizeof(Packet::header_checksum); j++) {
+            array[i][num]->header_checksum[j] = header_checksum[0][j];
+        }
+
+        for (int j = 0; j < (int) sizeof(Packet::marker); j++) {
+            array[i][num]->marker[j] = marker[j];
         }
     }