From 1d4ebbd7faa2a06ad5fb624f5f4feab52c62a0a2 Mon Sep 17 00:00:00 2001
From: Markus Hitter <mah@jump-ing.de>
Date: Sat, 28 May 2016 14:56:04 +0200
Subject: [PATCH] Display: queue up display_set_cursor(), too.

---
 display.c         | 19 +++++++++++++++++++
 display_hd44780.c | 17 -----------------
 display_ssd1306.c | 44 ++++++++++++++++++--------------------------
 3 files changed, 37 insertions(+), 43 deletions(-)

diff --git a/display.c b/display.c
index 96564dc..454b703 100644
--- a/display.c
+++ b/display.c
@@ -37,6 +37,25 @@ void display_clear(void) {
   display_writechar((uint8_t)low_code_clear);
 }
 
+/**
+  Sets the cursor to the given position.
+
+  \param line   The vertical cursor position to set, in lines. First line is
+                zero.
+
+  \param column The horizontal cursor position to set. In characters on
+                character based displays, in pixels on pixel based displays.
+                First column is zero.
+
+  Use this directly for debugging purposes, only. Regular display updates
+  happen in display_clock().
+*/
+void display_set_cursor(uint8_t line, uint8_t column) {
+  display_writechar((uint8_t)low_code_set_cursor);
+  display_writechar((uint8_t)line);
+  display_writechar((uint8_t)column);
+}
+
 /**
   Prints a character at the current cursor position.
 
diff --git a/display_hd44780.c b/display_hd44780.c
index 566259d..488407c 100644
--- a/display_hd44780.c
+++ b/display_hd44780.c
@@ -37,23 +37,6 @@ void display_init(void) {
   displaybus_write(0x0C, parallel_4bit_instruction);
 }
 
-/**
-  Sets the cursor to the given position.
-
-  \param line   The vertical cursor position to set, in lines. First line is
-                zero. Line height is character height, which is currently
-                fixed to 8 pixels.
-
-  \param column The horizontal cursor position to set, in pixels. First
-                column is zero.
-
-  Use this for debugging purposes, only. Regular display updates happen in
-  display_clock().
-*/
-void display_set_cursor(uint8_t line, uint8_t column) {
-  // Currently unimplemented.
-}
-
 /**
   Show a nice greeting. Pure eye candy.
 */
diff --git a/display_ssd1306.c b/display_ssd1306.c
index ffa7716..e6a4c5f 100644
--- a/display_ssd1306.c
+++ b/display_ssd1306.c
@@ -35,8 +35,6 @@
 
   TODO list:
 
-    - Move code in display_set_cursor() would to display_tick().
-
     - Lot's of prettification. Like a nice background picture with the Teacup
       logo, like "Welcome to Teacup" as a greeting screen, like writing numbers
       to readable places and so on.
@@ -114,30 +112,6 @@ void display_init(void) {
   }
 }
 
-/**
-  Sets the cursor to the given position.
-
-  \param line   The vertical cursor position to set, in lines. First line is
-                zero. Line height is character height, which is currently
-                fixed to 8 pixels.
-
-  \param column The horizontal cursor position to set, in pixels. First
-                column is zero.
-
-  Use this for debugging purposes, only. Regular display updates happen in
-  display_clock().
-*/
-void display_set_cursor(uint8_t line, uint8_t column) {
-
-  // Enter command mode.
-  displaybus_write(0x00, 0);
-  // Set line.
-  displaybus_write(0xB0 | (line & 0x03), 0);
-  // Set column.
-  displaybus_write(0x00 | (column & 0x0F), 0);
-  displaybus_write(0x10 | ((column >> 4) & 0x0F), 1);
-}
-
 /**
   Show a nice greeting. Pure eye candy.
 */
@@ -220,6 +194,24 @@ void display_tick() {
         displaybus_write(0x02, 1);
         break;
 
+      case low_code_set_cursor:
+        /**
+          Set the cursor to the given position.
+
+          This is a three-byte control command, so we fetch additional bytes
+          from the queue and cross fingers they're actually there.
+        */
+        // Enter command mode.
+        displaybus_write(0x00, 0);
+        // Set line.
+        buf_pop(display, data);
+        displaybus_write(0xB0 | (data & 0x03), 0);
+        // Set column.
+        buf_pop(display, data);
+        displaybus_write(0x00 | (data & 0x0F), 0);
+        displaybus_write(0x10 | ((data >> 4) & 0x0F), 1);
+        break;
+
       default:
         // Should be a printable character.
         index = data - 0x20;