From e2d789ccd0adfc301b58af41598311a9705b02f6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?King=20K=C3=A9vin?= <kingkevin@cuvoodoo.info>
Date: Thu, 23 Jun 2022 10:12:40 +0200
Subject: [PATCH] add init mode

---
 main.c | 52 +++++++++++++++++++++++++++++++---------------------
 1 file changed, 31 insertions(+), 21 deletions(-)

diff --git a/main.c b/main.c
index 9e0cc37..db7cd35 100644
--- a/main.c
+++ b/main.c
@@ -52,7 +52,7 @@
 // the functions we can call over I²C
 enum i2c_mode_t {
 	// custom modes
-	MODE_CLEAR_DISPLAY, // clear display
+	MODE_INIT, // initialise HD44780
 	MODE_LINE1, // write to line 1
 	MODE_LINE2, // write to line 2
 	MODE_DISPLAY_ON, // turn display on
@@ -60,9 +60,10 @@ enum i2c_mode_t {
 	MODE_BRIGHTNESS, // set backlight brightness
 
 	// raw instructions, directly mapping to HD44780
-	MODE_DISPLAY,
+	MODE_CLEAR_DISPLAY,
 	MODE_RETURN_HOME,
 	MODE_ENTRY_MODE_SET,
+	MODE_DISPLAY,
 	MODE_CURSOR_DISPLAY_SHIFT,
 	MODE_FUNCTION_SET,
 	MODE_CGRAM_ADDR,
@@ -188,6 +189,30 @@ static void hd44780_write_data(uint8_t data)
 	hd44780_write_byte(data);
 }
 
+static void hd44780_init(void)
+{
+	// configure display (as per datasheet)
+	IWDG_KR = IWDG_KR_KEY_REFRESH; // reset watchdog
+	HD44780_RS_PORT->ODR.reg &= ~HD44780_RS_PIN; // set low for instruction
+	hd44780_data_direction(false); // switch to write direction
+	wait_10us(4000 + 1000); // wait 40 ms after power up
+	hd44780_write_nibble(3); // 1st function write set to go to state 1 (8-bit) or 2 (4-bit first nibble) (BF cannot be checked)
+	wait_10us(410 + 100); // wait 4.1 ms
+	hd44780_write_nibble(3); // 2st function write set to go to state 1 (8-bit) or 3 (4-bit second nibble) (BF cannot be checked)
+	wait_10us(10 + 1); // wait 100 us
+	hd44780_write_nibble(3); // 3rd function write set to go to state 1 (8-bit) (BF cannot be checked)
+	wait_10us(4 + 1); // wait 37 us
+	hd44780_write_nibble(2); // switch to 4-bit mode
+	wait_10us(4 + 1); // wait 37 us (BF could be checked at this point)
+	// we are now for sure in 8-bit more (and could switch do 4-bit). 8-bit mode is actually the default after power up
+	IWDG_KR = IWDG_KR_KEY_REFRESH; // reset watchdog
+	hd44780_write_instruction(0x28); // function set (DL=1: 4-bit mode, N=1: 2 lines, F=0: 5x8 dots)
+	hd44780_write_instruction(0x01); // display clear
+	hd44780_write_instruction(0x06); // entry mode set
+	hd44780_write_instruction(0x02); // return home
+	hd44780_write_instruction(0x0c); // display on
+}
+
 void main(void)
 {
 	sim(); // disable interrupts (while we reconfigure them)
@@ -277,25 +302,7 @@ void main(void)
 	TIM2->EGR.fields.UG = 1; // force reload of values
 	TIM2->CR1.fields.CEN = 1; // enable timer
 
-	// configure display (as per datasheet)
-	IWDG_KR = IWDG_KR_KEY_REFRESH; // reset watchdog
-	HD44780_RS_PORT->ODR.reg &= ~HD44780_RS_PIN; // set low for instruction
-	hd44780_data_direction(false); // switch to write direction
-	wait_10us(4000 + 1000); // wait 40 ms after power up
-	hd44780_write_nibble(3); // 1st function write set to go to state 1 (8-bit) or 2 (4-bit first nibble) (BF cannot be checked)
-	wait_10us(410 + 100); // wait 4.1 ms
-	hd44780_write_nibble(3); // 2st function write set to go to state 1 (8-bit) or 3 (4-bit second nibble) (BF cannot be checked)
-	wait_10us(10 + 1); // wait 100 us
-	hd44780_write_nibble(3); // 3rd function write set to go to state 1 (8-bit) (BF cannot be checked)
-	wait_10us(4 + 1); // wait 37 us
-	hd44780_write_nibble(2); // switch to 4-bit mode
-	wait_10us(4 + 1); // wait 37 us (BF could be checked at this point)
-	// we are now for sure in 8-bit more (and could switch do 4-bit). 8-bit mode is actually the default after power up
-	IWDG_KR = IWDG_KR_KEY_REFRESH; // reset watchdog
-	hd44780_write_instruction(0x28); // function set (DL=1: 4-bit mode, N=1: 2 lines, F=0: 5x8 dots)
-	hd44780_write_instruction(0x08); // display off
-	hd44780_write_instruction(0x01); // display clear
-	hd44780_write_instruction(0x06); // entry mode set
+	hd44780_init(); // initialise display
 
 	rim(); // re-enable interrupts
 
@@ -312,6 +319,9 @@ void main(void)
 				i2c_input_new = false; // clear flag
 				// process mode switch
 				switch (i2c_mode) {
+				case MODE_INIT: // re-initialise display
+					hd44780_init();
+					break;
 				case MODE_CLEAR_DISPLAY: // clear display
 					hd44780_write_instruction(0x01); // clear display instruction
 					break;