From b20c272c8ebc261ee1c3ba498ef5d4dad43549ba Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?King=20K=C3=A9vin?= <kingkevin@cuvoodoo.info>
Date: Sun, 27 Sep 2020 11:56:31 +0200
Subject: [PATCH] led_tm1637: allow the display to be upside down

---
 lib/led_tm1637.c | 28 ++++++++++++++++++++++++++--
 lib/led_tm1637.h |  4 ++--
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/lib/led_tm1637.c b/lib/led_tm1637.c
index a096066..76f4b48 100644
--- a/lib/led_tm1637.c
+++ b/lib/led_tm1637.c
@@ -48,6 +48,8 @@ static enum led_tm1637_brightness_t display_brightness = LED_TM1637_14DIV16;
 static bool display_on = false;
 /** display buffer */
 static uint8_t led_tm1637_digits[4] = {0};
+/** if the display is upside down */
+bool led_tm1637_updown = false;
 
 /** ASCII characters encoded for the 7 segments digit block
  *  @note starts with space
@@ -150,8 +152,24 @@ static const uint8_t ascii_7segments[] = {
 	0x40, // 0b01000000 ~
 };
 
-void led_tm1637_setup(void)
+
+/** convert the data for upside down displays
+ *  @param[in] data the data to be converted
+ *  @return the upside down data
+ */
+static uint8_t led_tm1637_rotate(uint8_t data)
 {
+	uint8_t converted = 0;
+	converted |= (data & 0xc0); // keep g and dot
+	converted |= (data << 3) & 0x38; // rotate abc
+	converted |= (data >> 3) & 0x07; // rotate def
+	return converted;
+}
+
+void led_tm1637_setup(bool updown)
+{
+	led_tm1637_updown = updown; // remember if the display is upside down
+
 	// configure GPIO for CLK and DIO signals
 	rcc_periph_clock_enable(GPIO_RCC(LED_TM1637_CLK_PIN)); // enable clock for GPIO peripheral
 	gpio_set(GPIO_PORT(LED_TM1637_CLK_PIN), GPIO_PIN(LED_TM1637_CLK_PIN)); // idle high
@@ -246,7 +264,13 @@ static bool led_tm1637_write(const uint8_t* data, size_t length)
 static bool led_tm1637_update(void)
 {
 	const uint8_t write[] = { 0x40 }; // command: write data, automatic address adding, normal
-	const uint8_t data[] = { 0xc0, led_tm1637_digits[0], led_tm1637_digits[1], led_tm1637_digits[2], led_tm1637_digits[3] }; // set digits (start at address 0)
+	uint8_t data[] = { 0xc0, led_tm1637_digits[0], led_tm1637_digits[1], led_tm1637_digits[2], led_tm1637_digits[3] }; // set digits (start at address 0)
+	if (led_tm1637_updown) { // rotate data
+		data[1] = led_tm1637_rotate(led_tm1637_digits[3]);
+		data[2] = led_tm1637_rotate(led_tm1637_digits[2]) | (led_tm1637_digits[1] & 0x80); // keep the : for the time
+		data[3] = led_tm1637_rotate(led_tm1637_digits[1]) & 0x7f; // remove the : for the time
+		data[4] = led_tm1637_rotate(led_tm1637_digits[0]);
+	}
 	const uint8_t control[] = { (display_on ? 0x88 : 0x80) + (display_brightness & 0x7) }; // command to turn display on/off and set brightness
 	return led_tm1637_write(write, LENGTH(write)) && led_tm1637_write(data, LENGTH(data)) && led_tm1637_write(control, LENGTH(control)); // send commands
 }
diff --git a/lib/led_tm1637.h b/lib/led_tm1637.h
index 57d0246..e26657d 100644
--- a/lib/led_tm1637.h
+++ b/lib/led_tm1637.h
@@ -22,8 +22,9 @@ enum led_tm1637_brightness_t {
 };
 
 /** setup communication with TM1637 IC
+ *  @param[in] updown if the display is upside down
  */
-void led_tm1637_setup(void);
+void led_tm1637_setup(bool updown);
 /** switch display on
  *  @return if transmission succeeded
  */
@@ -56,4 +57,3 @@ bool led_tm1637_time(uint8_t hours, uint8_t minutes);
  *  @return if transmission succeeded
  */
 bool led_tm1637_text(char* text);
-