From 3cd86e1b09c789248fc20a003cb05ade55fef331 Mon Sep 17 00:00:00 2001
From: Carsten Keller <mail@carstenkeller.dev>
Date: Sun, 9 Jun 2024 17:58:20 +0200
Subject: [PATCH] Printe String in Display

---
 Source/Display.cpp           | 65 ++++++++++++++++++++++++++++++++++--
 Source/Display.hpp           |  9 +++--
 Source/ElektronischeLast.cpp |  2 ++
 3 files changed, 71 insertions(+), 5 deletions(-)

diff --git a/Source/Display.cpp b/Source/Display.cpp
index 85d8630..216c263 100644
--- a/Source/Display.cpp
+++ b/Source/Display.cpp
@@ -5,6 +5,7 @@
  *      Author: Carst
  */
 
+#include <cstring>
 #include <stm32g0xx_ll_gpio.h>
 #include "STM32G071KBT6.hpp"
 #include "Display.hpp"
@@ -41,7 +42,11 @@ namespace ElektronischeLast
     switch (this->current_state)
     {
       case StateIdle:
-        // do nothing;
+        if(this->new_data)
+        {
+          this->new_data = false;
+          this->current_state = StateWriteData;
+        }
         break;
       case StateDelay:
         if(this->timer_elapsed())
@@ -109,6 +114,17 @@ namespace ElektronischeLast
         this->start_timer(1UL);
         this->next_state = StateIdle;
         break;
+      case StateWriteData:
+        write_data_4bit((std::uint8_t)this->string[this->pointer++]);
+        if(this->string[this->pointer] == '\0')
+        {
+          this->next_state = StateIdle;
+        }
+        else
+        {
+          this->next_state = StateWriteData;
+        }
+        break;
       default:
         break;
     }
@@ -128,12 +144,14 @@ namespace ElektronischeLast
 
   void Display::set_cursor(Line_t line, std::uint32_t position)
   {
-
+    lcd_cmd(0x80u | line | (position & 0x7F));
   }
 
   void Display::print(const char* const string)
   {
-
+    strncpy(this->string, string, sizeof(this->string));
+    this->pointer = 0U;
+    this->new_data = true;
   }
 
   bool Display::timer_elapsed(void)
@@ -179,4 +197,45 @@ namespace ElektronischeLast
     pulse_delay();
     LL_GPIO_ResetOutputPin(GPIOB, PIN_E);
   }
+
+  /// \brief write command to lcd and wait until busy is gone
+  /// \param[in] cmd command to transfer
+  void Display::lcd_cmd(uint8_t cmd)
+  {
+    write_command_4bit(cmd);
+    this->start_timer(1UL);
+  }
+
+  /// \brief write data to display
+  /// \param[in] data data which to write to display
+  void Display::lcd_data(uint8_t data)
+  {
+    write_data_4bit(data);
+    this->start_timer(1UL);
+  }
+
+  /// \brief write data to lcd in 4 bit mode
+  /// \details write data given by \p data to lcd.
+  /// First write upper nibble and in second step lower nibble
+  /// \param[in] data data to transfer
+  void Display::write_data_4bit(uint8_t data)
+  {
+    // RS=high, RW=low
+    LL_GPIO_SetOutputPin(GPIOB, PIN_RS | PIN_RW  << GPIO_BSRR_BR0_Pos | PIN_E << GPIO_BSRR_BR0_Pos);
+    std::uint32_t tmp = data >> 4U;
+    tmp |= ((~(data >> 4U) & 0xFU) << GPIO_BSRR_BR0_Pos);
+    LL_GPIO_SetOutputPin(GPIOB, tmp);
+    __NOP();
+    LL_GPIO_SetOutputPin(GPIOB, PIN_E);
+    pulse_delay();
+    LL_GPIO_ResetOutputPin(GPIOB, PIN_E);
+    tmp = data & 0x0FU;
+    tmp |= ((~data & 0xFU) << GPIO_BSRR_BR0_Pos);
+    LL_GPIO_SetOutputPin(GPIOB, tmp);
+    __NOP();
+    LL_GPIO_SetOutputPin(GPIOB, PIN_E);
+    pulse_delay();
+    LL_GPIO_ResetOutputPin(GPIOB, PIN_E);
+    this->start_timer(1UL);
+  }
 }
diff --git a/Source/Display.hpp b/Source/Display.hpp
index 0b7c072..e6cff51 100644
--- a/Source/Display.hpp
+++ b/Source/Display.hpp
@@ -85,7 +85,7 @@ namespace ElektronischeLast
         StateInit08,
         StateInit09,
         StateInit10,
-
+        StateWriteData,
       } State_t;
 
       void init(void);
@@ -97,11 +97,16 @@ namespace ElektronischeLast
       State_t current_state;
       State_t next_state;
       std::uint32_t timer;
+      char string[17];
+      std::uint8_t pointer;
+      bool new_data;
       bool timer_elapsed(void);
       void start_timer(std::uint32_t timeout);
-      void wait_while_busy(void);
+      void lcd_cmd(uint8_t cmd);
+      void lcd_data(uint8_t data);
       void write_command_8bit_4pin(std::uint32_t data);
       void write_command_4bit(std::uint32_t command);
+      void write_data_4bit(uint8_t data);
   };
 }
 
diff --git a/Source/ElektronischeLast.cpp b/Source/ElektronischeLast.cpp
index 6e57217..597b9da 100644
--- a/Source/ElektronischeLast.cpp
+++ b/Source/ElektronischeLast.cpp
@@ -110,6 +110,8 @@ int main (void)
 
   PIDController_Init(&pid);
 
+  lcd.print("Miep Miep");
+
   while(1)
   {
     led.blink();