More comments

src/main.c

@@ -3,9 +3,6 @@
 #include <stdio.h>
 #include <unistd.h>
 
-unsigned *SDApinctrl = (void *)(IO_BANK0_BASE + IO_BANK0_GPIO0_CTRL_OFFSET);
-unsigned *SCLpinctrl = (void *)(IO_BANK0_BASE + IO_BANK0_GPIO1_CTRL_OFFSET);
-
 const uint8_t init[4] = {0x21, 0xa0, 0xe1, 0x81};
 const uint8_t zeile[8] = {0x00, 0x02, 0x04, 0x06, 0x08, 0x10, 0x12, 0x14};
 const uint8_t fill[17] = {0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
@@ -34,13 +31,20 @@ const uint8_t matrix[9][17] = {
 };
 int main()
 {
-
+    // clock enable: 100000 baud (bit/s)
     i2c_init(i2c_default, 100000);
+    // Pin 0 and 1 are given I2C functionality (they're the ones connected to the led matrix)
     gpio_set_function(0, GPIO_FUNC_I2C);
     gpio_set_function(1, GPIO_FUNC_I2C);
 
-    gpio_pull_up(1);
-    gpio_pull_up(0);
+    // refer to page 439 in RP2040, redundant with write_blocking - pins are used as output (write enable) (sort of)
+    // gpio_pull_up(1);
+    // gpio_pull_up(0);
+
+    // 0x70 i2c address for 28 pin (refer to matrix.pdf page 21)
+    // can't be directly written cuz we need pointers
+    // system setup (clock enable), ROW/INT set, dimming, display setup
+    // const uint8_t init[4] = {0x21, 0xa0, 0xe1, 0x81};
 
     i2c_write_blocking(i2c_default, 0x70, &init[0], 1, false);
     i2c_write_blocking(i2c_default, 0x70, &init[1], 1, false);
@@ -55,6 +59,7 @@ int main()
     {
         i2c_write_blocking(i2c_default, 0x70, matrix[i], 17, false);
 
+        // sleep
         for (int j = 0; j < 10000000; j++)
         {
             volatile int i = 0;