constrain traces to the screen

main.c

@@ -142,9 +142,9 @@ int main(void) {
 
     IntMasterEnable();
 
-    uint8_t voltage_scale = 0;
+    uint8_t voltage_scale = 4; // 2v
-    uint8_t time_scale = 0;
+    uint8_t time_scale = 5; // 20us
-    uint8_t trigger_mode = 1;
+    uint8_t trigger_mode = 1; // rising
 
     while (true) {
         // calculate cpu usage
@@ -238,9 +238,12 @@ int main(void) {
         float fVoltsPerDiv = gVoltageScale[voltage_scale];
         float fScale = (VIN_RANGE * PIXELS_PER_DIV)/((1 << ADC_BITS) * fVoltsPerDiv);
 
-        GrContextForegroundSet(&sContext, ClrPink);
+        GrContextForegroundSet(&sContext, ClrYellow);
         for(j=0; j<LOCAL_BUF_LEN; j++) {
-            #define TRANSPOSE(x) (HEIGHT/2) - (int)roundf(fScale * ((int)x - ADC_OFFSET));
+            #define MIN(a,b) (((a)<(b))?(a):(b))
+            #define MAX(a,b) (((a)>(b))?(a):(b))
+            #define CONSTRAIN(x) MAX(MIN(HEIGHT - 1, x), 0)
+            #define TRANSPOSE(x) CONSTRAIN((HEIGHT/2) - (int)roundf(fScale * ((int)x - ADC_OFFSET)))
             uint32_t upper,lower, current, last;
 
             if (j==0) {
@@ -250,10 +253,6 @@ int main(void) {
             } else {
                 current = TRANSPOSE(local_adc_buffer[j]);
                 
-                // couldn't find these anywhere
-                #define MIN(a,b) (((a)<(b))?(a):(b))
-                #define MAX(a,b) (((a)>(b))?(a):(b))
-
                 upper = MAX(current, last);
                 lower = MIN(current, last);