From 6d7141db0c73af34fd887fda9723c77aaaf1e349 Mon Sep 17 00:00:00 2001
From: Trygve Laugstøl <trygvis@inamo.no>
Date: Fri, 29 May 2015 00:00:05 +0200
Subject: o Initial import of Phone Remote firmware, forked from the old soil
 moisture project.

---
 LiquidCrystal.c | 141 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100644 LiquidCrystal.c

(limited to 'LiquidCrystal.c')

diff --git a/LiquidCrystal.c b/LiquidCrystal.c
new file mode 100644
index 0000000..becc07e
--- /dev/null
+++ b/LiquidCrystal.c
@@ -0,0 +1,141 @@
+#include "LiquidCrystal.h"
+#include "nrf_gpio.h"
+#include "app_timer.h"
+
+/*
+ * Arduino | LCD | nrf51
+ *      D4 | DB4 | P0.16
+ *      D5 | DB5 | P0.17
+ *      D6 | DB6 | P0.18
+ *      D7 | DB7 | P0.10
+ *      D8 |  RS | P0.20, register select. 0=instruction (write), 0=busy (read), 1=data
+ *      D9 |  EN | P0.23, clock, data is clocked in/out on falling edge
+ *     D10 | DB4 | P0.24
+ */
+
+enum liquid_crystal_cmd {
+    LIQUID_CRYSTAL_CMD_CLEAR = 0x01,
+    LIQUID_CRYSTAL_CMD_RETURN_HOME = 0x02,
+    LIQUID_CRYSTAL_CMD_ENTRY_MODE_SET = 0x04,
+    LIQUID_CRYSTAL_CMD_DISPLAY = 0x08,
+    LIQUID_CRYSTAL_CMD_SHIFT = 0x10,
+    LIQUID_CRYSTAL_CMD_FUNCTION_SET = 0x20,
+    LIQUID_CRYSTAL_CMD_SET_CGRAM_ADDDRESS = 0x40,
+    LIQUID_CRYSTAL_CMD_SET_DDRAM_ADDDRESS = 0x80,
+};
+
+static struct {
+    uint8_t pin_db4;
+    uint8_t pin_db5;
+    uint8_t pin_db6;
+    uint8_t pin_db7;
+    uint8_t pin_rs;
+    uint8_t pin_en;
+
+    app_gpiote_user_id_t gpio_user_id;
+} data = { .pin_db4 = 16, .pin_db5 = 17, .pin_db6 = 18, .pin_db7 = 19, .pin_rs =
+        20, .pin_en = 23, };
+
+static uint32_t ticks_per_ms;
+
+static void event_handler() {
+}
+
+static void wait_ms(uint32_t ms) {
+    uint32_t ticks;
+
+    app_timer_cnt_get(&ticks);
+
+    const uint32_t end_ticks = ticks + ms * ticks_per_ms;
+
+    do {
+        app_timer_cnt_get(&ticks);
+    } while (ticks < end_ticks);
+}
+
+static void write_4(uint8_t value) {
+    nrf_gpio_pin_write(data.pin_db4, value & 0x01);
+    nrf_gpio_pin_write(data.pin_db5, value & 0x02);
+    nrf_gpio_pin_write(data.pin_db6, value & 0x04);
+    nrf_gpio_pin_write(data.pin_db7, value & 0x08);
+
+    nrf_gpio_pin_set(data.pin_en);
+    nrf_gpio_pin_clear(data.pin_en);
+}
+
+static void write_value(uint8_t value, bool is_data) {
+    nrf_gpio_pin_write(data.pin_rs, is_data);
+
+    write_4(value >> 4);
+    write_4(value);
+}
+
+static void begin() {
+    nrf_gpio_pin_clear(data.pin_rs);
+    nrf_gpio_pin_clear(data.pin_en);
+
+    // SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION!
+    // according to datasheet, we need at least 40ms after power rises above 2.7V
+    // before sending commands. Arduino can turn on way before 4.5V so we'll wait 50
+    wait_ms(50);
+
+    write_4(0x03);
+    wait_ms(5); // 4.5ms
+
+    write_4(0x03);
+    wait_ms(5); // 4.5ms
+
+    write_4(0x03);
+    wait_ms(5); // 4.5ms
+
+    write_4(0x02);
+
+    write_value(LIQUID_CRYSTAL_CMD_DISPLAY, false);
+
+//	_displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF;
+    liquid_crystal_display(true, true, true);
+}
+
+void liquid_crystal_write_char(char chr) {
+    write_value(chr, true);
+}
+
+void liquid_crystal_write_string(char *chr) {
+    while (*chr != '\0') {
+        liquid_crystal_write_char(*chr);
+    }
+}
+
+uint32_t liquid_crystal_display(bool display_on, bool cursor_on, bool blink) {
+    uint8_t value = LIQUID_CRYSTAL_CMD_DISPLAY;
+
+    value |= display_on ? 0x04 : 0x00;
+    value |= cursor_on ? 0x02 : 0x00;
+    value |= blink ? 0x01 : 0x00;
+
+    write_value(value, false);
+
+    return NRF_SUCCESS;
+}
+
+uint32_t liquid_crystal_init(uint32_t _ticks_per_ms) {
+    ticks_per_ms = _ticks_per_ms;
+
+    uint32_t err_code = app_gpiote_user_register(&data.gpio_user_id, 0x0000,
+            0x0000, event_handler);
+
+    if (err_code != NRF_SUCCESS) {
+        return err_code;
+    }
+
+    nrf_gpio_cfg_output(data.pin_db4);
+    nrf_gpio_cfg_output(data.pin_db5);
+    nrf_gpio_cfg_output(data.pin_db6);
+    nrf_gpio_cfg_output(data.pin_db7);
+    nrf_gpio_cfg_output(data.pin_rs);
+    nrf_gpio_cfg_output(data.pin_en);
+
+    begin(data);
+
+    return NRF_SUCCESS;
+}
-- 
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