Rebuild the code and the board for a 3-wire protocol

This required switching to the display's 4-wire protocol so that I could use some of the pins on the shift register for register select and enable.

display/display.c

@@ -15,44 +15,87 @@ You should have received a copy of the GNU General Public License along with Lum
 #include <util/delay.h>
 #include <base.h>
 
-void display_strobe_line(gpio_t *line) {
-    set_line(line);
-    _delay_us(50);
-    clear_line(line);
-    _delay_us(50);
+#define ENABLE   _BV(5)
+#define CHARCODE _BV(4)
+
+void ping(gpio_t *light) {
+    set_line(light);
+    _delay_ms(100);
+    clear_line(light);
+    _delay_ms(100);
+}
+
+
+void send_half_code(display_t *disp, uint8_t reg, uint8_t data) {
+    sr_send_msb(&disp->reg, (reg ? CHARCODE : 0) | data << 2);
+    _delay_us(1);
+    sr_send_msb(&disp->reg, (ENABLE | (reg ? CHARCODE : 0) | data) << 2);
+    _delay_us(1);
+    sr_send_msb(&disp->reg, ((reg ? CHARCODE : 0) | data) << 2);
+    _delay_us(1);
+}
+
+
+void send_code(display_t *disp, uint8_t reg, uint8_t data) {
+    send_half_code(disp, reg, data >> 4);
+    send_half_code(disp, reg, data & 0xf);
 }
 
 void write_instruction(display_t *disp, uint8_t bitcode) {
-    clear_line(&disp->register_select);
-    sr_send_msb(&disp->reg, bitcode);
-    display_strobe_line(&disp->enable);
+    send_code(disp, 0, bitcode);
 }
 
 void write_char(display_t *disp, uint8_t bitcode) {
-    set_line(&disp->register_select);
-    sr_send_msb(&disp->reg, bitcode);
-    display_strobe_line(&disp->enable);
+    send_code(disp, 1, bitcode);
+    _delay_us(100);
 }
 
 void display_init(display_t *disp) {
     sr_initialize(&disp->reg);
-    set_line_direction(&disp->register_select, LINE_OUT);
-    set_line_direction(&disp->enable, LINE_OUT);
-    write_instruction(disp, 0b00111000);
+
+    /* Initializing for 4-bit channel */
+    send_half_code(disp, 0, 0b0011);
+    _delay_ms(5);
+    send_half_code(disp, 0, 0b0011);
+    _delay_us(150);
+    send_half_code(disp, 0, 0b0011);
+    _delay_us(100);
+    send_half_code(disp, 0, 0b0010);
+    _delay_us(100);
+
+    /* Function set, 4-bit channel, two lines, 5x10 dots */
+    write_instruction(disp, 0b00101000);
+    _delay_us(100);
+
+    /* display off */
+    write_instruction(disp, 0b00001000);
+    _delay_us(100);
+
+    /* display clear */
+    write_instruction(disp, 0b00000001);
+    _delay_ms(3);
+
+    /* set entry mode */
+    write_instruction(disp, 0b00000110);
+    _delay_us(100);
+
+    /* display on */
+    write_instruction(disp, 0b00001100);
+    _delay_us(100);
 }
 
 void display_clear(display_t *disp) {
     write_instruction(disp, 0b00000001);
-    _delay_ms(3);
+    _delay_us(100);
     write_instruction(disp, 0b00000010);
-    _delay_ms(3);
+    _delay_us(100);
 
 }
 
 void display_enable(display_t *disp) {
-    write_instruction(disp, 0b00001100);
+    write_instruction(disp, _BV(5));
     _delay_us(100);
-    write_instruction(disp, 0b00000100);
+    write_instruction(disp, _BV(5) | _BV(3));
     _delay_us(100);
 }
 
@@ -68,4 +111,3 @@ void display_write_message(display_t *disp, const char *msg) {
     }
 }
 
-

display/display.h

@@ -46,8 +46,10 @@ You should have received a copy of the GNU General Public License along with Lum
 
 typedef struct DISPLAY {
     shift_register_t reg;
+    /*
     gpio_t register_select;
     gpio_t enable;
+    */
 } display_t;
 
 void display_init(display_t *);

rfm_diagnostic/main.c

@@ -159,16 +159,29 @@ void display_bits(display_t *display, uint8_t bits) {
     }
 }
 
+void strobe_light(gpio_t *light) {
+    set_line(light);
+    _delay_ms(100);
+    clear_line(light);
+    _delay_ms(100);
+}
+
 int main(void) {
     display_t display = {
         .reg = {
-            .output         = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 5 },
-            .latch_clock    = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 6 },
-            .shift_clock    = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 7 },
+            .output         = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 7 },
+            .shift_clock    = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 6 },
+            .latch_clock    = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 5 },
         },
-        .register_select    = { .ddr = &DDRF, .port = &PORTF, .pin = &PINF, .addr = 1 },
-        .enable             = { .ddr = &DDRF, .port = &PORTF, .pin = &PINF, .addr = 0 },
     };
+
+    gpio_t light = { .ddr = &DDRC, .port = &PORTC, .pin = &PINC, .addr = 7 };
+    set_line_direction(&light, LINE_OUT);
+    strobe_light(&light);
+    strobe_light(&light);
+    strobe_light(&light);
+
+    _delay_ms(15);
     display_init(&display);
 
     rfm_t rfm = {
@@ -184,16 +197,13 @@ int main(void) {
 
     rfm_initialize(&rfm);
 
-    _delay_ms(15);
     display_enable(&display);
 
     display_clear(&display);
     display_write_message(&display, "Waking up");
     _delay_ms(1000);
 
-    /*
     rfm_set_mode(&rfm, standby);
-    */
     rfm_listen(&rfm);
 
     while(1) {