1 files changed, 127 insertions, 0 deletions
diff --git a/src/ssd1306_display_driver.c b/src/ssd1306_display_driver.c
new file mode 100644
index 0000000..0e7d4cc
--- /dev/null
+++ b/src/ssd1306_display_driver.c
@@ -0,0 +1,127 @@
+#include <util/twi.h>
+#include <stdio.h>
+#include <util/delay.h>
+#include <string.h>
+#include "i2c.h"
+#include "ssd1306_display_driver.h"
+
+
+#define SSD1306_ADDR      0x3c
+#define SSD1306_CMD_REG   0x00
+#define SSD1306_DATA_REG  0x40
+
+//on the datasheet we have 32 extra rows (4 more pages) of GDRAM that don't fit on the display; we just ignore them everywhere
+#define SCREEN_PAGE_CNT   SCREEN_RES_Y / 8 
+
+#define I2C_WRITE   0
+#define I2C_READ    1
+
+
+
+void screen_init() {
+#ifdef DEBUG_BUILD
+    printf("initlizing SSD1306 display driver\n");
+#endif
+  //turn on screen while we configure shit, it might look cooler
+  i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0xaf); 
+ 
+  //don't inverse display
+  i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0xa6); 
+
+  //set contrast to 255 (try chainging?)
+  i2c_write_reg_multi(SSD1306_ADDR, SSD1306_CMD_REG, 2, (uint8_t[]){0x81, 0xff}); 
+
+  //set lower nibble of column ptr to 0
+  i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0x00); 
+  //set upper nibble of column ptr to 0
+  i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0x10); 
+
+  //memory mode is paging
+  i2c_write_reg_multi(SSD1306_ADDR, SSD1306_CMD_REG, 2, (uint8_t[]){0x20, 0x02}); 
+
+  //no vertical shift
+  i2c_write_reg_multi(SSD1306_ADDR, SSD1306_CMD_REG, 2, (uint8_t[]){0xd3, 0x00}); 
+
+  //page address is at 0
+  i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0xb0); 
+
+  //ram display start register is at 0
+  i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0x40); 
+
+  //column address 0 is mapped to seg0
+  i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0xa0);  //a1
+
+  i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0xc8); 
+
+
+  //set mux ratio to 32 mux 
+  i2c_write_reg_multi(SSD1306_ADDR, SSD1306_CMD_REG, 2, (uint8_t[]){0xa8, 0x1f});  
+
+  //alternative COM hardware mapping (stolen from lib)
+  i2c_write_reg_multi(SSD1306_ADDR, SSD1306_CMD_REG, 2, (uint8_t[]){0xda, 0x02});  
+
+  //volage regulator on
+  i2c_write_reg_multi(SSD1306_ADDR, SSD1306_CMD_REG, 2, (uint8_t[]){0x8d, 0x14});  
+
+
+  //set clock divider to zero, and oscillator frequency as high as it goes
+  //Maybe we save battery to run slower?
+  i2c_write_reg_multi(SSD1306_ADDR, SSD1306_CMD_REG, 2, (uint8_t[]){0xd5, 0xf0}); //TODO look
+
+  //deactivate scroll
+  i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0x2e); 
+
+}
+
+void screen_off() { i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0xaf); }
+
+void screen_on() { i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0xae); }
+
+void screen_update() {
+  for(int on_page = 0; on_page < SCREEN_PAGE_CNT; on_page++) {
+    i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0xb0 + on_page);
+    i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0x00);
+    i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0x10);
+    i2c_write_reg_multi(SSD1306_ADDR, SSD1306_DATA_REG, sizeof(screen_buffer), screen_buffer);
+  }
+}
+
+#ifdef DEBUG_BUILD
+//ugly code below
+
+void scroll_test() {
+  //sets scroll area to whole screen
+  i2c_write_reg_multi(SSD1306_ADDR, SSD1306_CMD_REG, 3, (uint8_t[]){0xa3, 0x00, 0x20});
+  //set up scroll options
+  i2c_write_reg_multi(SSD1306_ADDR, SSD1306_CMD_REG, 6, (uint8_t[]){0x29, 0x00, 0x00, 0x00, 0x04, 0x00});
+  //actually activate scroll
+  i2c_write_reg_multi(SSD1306_ADDR, SSD1306_CMD_REG, 6, (uint8_t[]){0x2f});
+}
+
+void screen_testdraw() {
+  unsigned int on_pix;
+  unsigned int on_page;
+
+  printf("running screen time tests\n");
+  printf("generating test image...\n");
+  for(on_pix = 0; on_pix < sizeof(screen_buffer); on_pix++) 
+    screen_buffer[on_pix] = ((uint8_t)0xaa << (on_pix % 8));
+
+  printf("page mode, individual byte per i2c call...\n");
+  for(on_page = 0; on_page < SCREEN_PAGE_CNT; on_page++) {
+    i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0xb0 + on_page);
+    i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0x00);
+    i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0x10);
+    for(on_pix = 0; on_pix < SCREEN_RES_X; on_pix++)
+      i2c_write_reg(SSD1306_ADDR, SSD1306_DATA_REG, screen_buffer[(on_page * 8) + on_pix]);
+  }
+  printf("page mode, 1 page per i2c call...\n");
+  for(on_page = 0; on_page < SCREEN_PAGE_CNT; on_page++) {
+    i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0xb0 + on_page);
+    i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0x00);
+    i2c_write_reg(SSD1306_ADDR, SSD1306_CMD_REG, 0x10);
+    i2c_write_reg_multi(SSD1306_ADDR, SSD1306_DATA_REG, SCREEN_RES_X, &screen_buffer[on_page * SCREEN_RES_X]);
+  }
+}
+
+#endif