Prototype LCD control

base/base.c

@@ -9,3 +9,13 @@ uint8_t rng_sample(rng_t *state) {
     state->seed = (state->a * state->seed + state->c) % state->mod;
     return state->seed;
 }
+
+/*
+void strobe_line(gpio_t *line, uint32_t us) {
+    set_line(line);
+    _delay_us(us);
+    clear_line(line);
+    _delay_us(us);
+}
+*/
+

base/base.h

@@ -1,8 +1,9 @@
-#include <avr/io.h>
-
 #ifndef __BASE_H__
 #define __BASE_H__
 
+#include <avr/io.h>
+#include <avr/delay.h>
+
 #define LINE_OUT 1
 #define LINE_IN  0
 

lcd/main.c

@@ -0,0 +1,100 @@
+#include <avr/io.h>
+#include <util/delay.h>
+#include <base.h>
+#include <spi.h>
+#include <reg.h>
+
+typedef struct HD44780 {
+    shift_register_t reg;
+    gpio_t register_select;
+    gpio_t enable;
+} hd44780_t;
+
+void strobe_line(gpio_t *line) {
+    set_line(line);
+    _delay_ms(1);
+    clear_line(line);
+    _delay_ms(1);
+}
+
+void hd44780_init(hd44780_t *disp) {
+    spi_initialize(disp);
+    set_line_direction(&disp->register_select, LINE_OUT);
+    set_line_direction(&disp->enable, LINE_OUT);
+    send_msb(&disp->reg, 0b00111100);
+}
+
+void hd44780_clear(hd44780_t *disp) {
+    clear_line(&disp->register_select);
+    send_msb(&disp->reg, 0b00000001);
+    _delay_ms(1);
+    strobe_line(&disp->enable);
+
+    send_msb(&disp->reg, 0b00000010);
+    _delay_ms(1);
+    strobe_line(&disp->enable);
+}
+
+void hd44780_display(hd44780_t *disp) {
+    clear_line(&disp->register_select);
+    send_msb(&disp->reg, 0b00001110);
+    _delay_ms(1);
+    strobe_line(&disp->enable);
+}
+
+void hd44780_write_char(hd44780_t *disp, uint8_t bitcode) {
+    set_line(&disp->register_select);
+    send_msb(&disp->reg, bitcode);
+    strobe_line(&disp->enable);
+}
+
+void hd44780_write(hd44780_t *disp) {
+    set_line(&disp->register_select);
+
+    hd44780_write_char(disp, 0b01001000);
+    hd44780_write_char(disp, 0b01000101);
+    hd44780_write_char(disp, 0b01001100);
+    hd44780_write_char(disp, 0b01001100);
+    hd44780_write_char(disp, 0b01001111);
+    hd44780_write_char(disp, 0b00101100);
+
+    hd44780_write_char(disp, 0b00100000);
+
+    hd44780_write_char(disp, 0b01001101);
+    hd44780_write_char(disp, 0b01011001);
+
+    hd44780_write_char(disp, 0b00100000);
+
+    hd44780_write_char(disp, 0b01000010);
+    hd44780_write_char(disp, 0b01000001);
+    hd44780_write_char(disp, 0b01010100);
+}
+
+int main(void) {
+    hd44780_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 },
+        },
+        .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);
+    clear_line(&light);
+
+    hd44780_init(&display);
+
+    hd44780_clear(&display);
+    _delay_ms(500);
+
+    hd44780_write(&display);
+    hd44780_display(&display);
+
+    set_line(&light);
+
+    while(1) { _delay_ms(1); }
+}
+

shift_register/reg.c

@@ -1,3 +1,4 @@
+#include <util/delay.h>
 #include <base.h>
 #include <reg.h>
 
@@ -11,15 +12,20 @@ void shift_register_initialize(shift_register_t *reg) {
     clear_line(&reg->latch_clock);
 }
 
-void send_byte_lsb(shift_register_t *reg, uint8_t byte) {
+void send_lsb(shift_register_t *reg, uint8_t byte) {
     for (uint8_t i = 0; i < 8; i++) {
         byte & _BV(i) ? set_line(&reg->output) : clear_line(&reg->output);
         strobe_line(&reg->shift_clock);
     }
+    clear_line(&reg->output);
+    strobe_line(&reg->latch_clock);
 }
 
-void shift_out(shift_register_t *reg, uint8_t byte) {
-    send_byte_lsb(reg, byte);
+void send_msb(shift_register_t *reg, uint8_t byte) {
+    for (int8_t i = 7; i >= 0; i--) {
+        byte & _BV(i) ? set_line(&reg->output) : clear_line(&reg->output);
+        strobe_line(&reg->shift_clock);
+    }
     clear_line(&reg->output);
     strobe_line(&reg->latch_clock);
 }

shift_register/reg.h

@@ -10,6 +10,7 @@ typedef struct SHIFT_REGISTER {
 
 
 void shift_register_initialize(shift_register_t *reg);
-void shift_out(shift_register_t *reg, uint8_t byte);
+void send_lsb(shift_register_t *reg, uint8_t byte);
+void send_msb(shift_register_t *reg, uint8_t byte);
 
 #endif