- Fixed drawing of round objects (Circles, Rounded Rects) using a lookup table

- Added function to read out the display_buffer via USB-Serial
 - Added basic structure and files for later complete firmware (still in progress)
 - Added Doc folder with schematic in it
 - Added Python script and batch file to read out the display buffer and open the image in gimp

Firmware/UART0.c

@@ -0,0 +1,200 @@
+/*
+ * UART0.c
+ *
+ * Created: Mon May 03 2021 19:57:05
+ *  Author Chris
+ */
+#include "UART0.h"
+
+#include "pico/stdlib.h"
+#include "hardware/irq.h"
+#include "hardware/uart.h"
+
+
+// ============================================================================================
+// Defines
+#define UART_ID 			uart0
+/*
+	Baudrate is supposed to be 1000000 (1 Mio.). Due to the overclocking and the not adjusted peripeheral clock (See Clock.c)
+	a alternative baudrate has to be defined in order to acheive a baudrate of 1000000. The given values has indentified 
+	experimentally by measuring via the logic analyzer,
+*/
+#define BAUD_RATE 			31250u
+#define DATA_BITS 			8
+#define STOP_BITS 			1
+#define PARITY    			UART_PARITY_NONE
+
+#define UART_TX_PIN 		28 // Not connected
+#define UART_RX_PIN 		17
+
+#define UART_BUFFER_SIZE	128
+
+
+// ============================================================================================
+// Variables
+struct UART_BUFFER_s
+{
+	uint8_t Data[UART_BUFFER_SIZE];
+	uint8_t	Read;
+	uint8_t	Write;
+} _UART_Buffer;
+
+volatile uint _Actual_Baudrate;
+
+
+// ============================================================================================
+// Function Declarations
+
+
+/*******************************************************************
+	Interrupt Service Routines
+*******************************************************************/
+void UART0_RX_ISR()
+{
+    while(uart_is_readable(UART_ID))
+	{
+       // Fetch the Received Byte
+	   _UART_Buffer.Data[_UART_Buffer.Write++] = uart_getc(UART_ID);		
+	
+		if(_UART_Buffer.Write == UART_BUFFER_SIZE)
+		{
+			_UART_Buffer.Write = 0;
+		}
+    }
+}
+
+
+/*******************************************************************
+	Functions
+*******************************************************************/
+void UART0_Init(void)
+{
+	_UART_Buffer.Read	= 0;
+	_UART_Buffer.Write	= 0;
+	
+	uart_init(UART_ID, 2400);
+
+	// Only Receive is needed for MIDI function
+//	gpio_set_function(UART_TX_PIN, GPIO_FUNC_UART);
+    gpio_set_function(UART_RX_PIN, GPIO_FUNC_UART);
+
+	_Actual_Baudrate = uart_set_baudrate(UART_ID, BAUD_RATE);
+
+	// Set UART flow control CTS/RTS, we don't want these, so turn them off
+	uart_set_hw_flow(UART_ID, false, false);
+
+	// Set our data format
+    uart_set_format(UART_ID, DATA_BITS, STOP_BITS, PARITY);
+
+    // Turn off FIFO's - we want to do this character by character
+    uart_set_fifo_enabled(UART_ID, false);
+
+    // Select correct interrupt for the UART we are using
+    int UART_IRQ = UART_ID == uart0 ? UART0_IRQ : UART1_IRQ;
+
+	// And set up and enable the interrupt handlers
+    irq_set_exclusive_handler(UART_IRQ, UART0_RX_ISR);
+    irq_set_enabled(UART_IRQ, true);
+
+	// Now enable the UART to send interrupts - RX only
+    uart_set_irq_enables(UART_ID, true, false);
+}
+
+uint UART0_Get_Actual_Baudrate(void)
+{
+	return _Actual_Baudrate;
+}
+
+void UART0_Send_Byte(uint8_t byte)
+{
+	while (!uart_is_writable(UART_ID))
+	{
+		tight_loop_contents();
+	}
+	
+	uart_putc(UART_ID, (char)byte);
+}
+
+void UART0_Send_Array(uint8_t* array, uint length)
+{
+	for(uint16_t i=0;i<length;i++)
+	{
+		UART0_Send_Byte(array[i]);
+	}
+}
+
+void UART0_Send_Int_Dec(uint val, uint8_t numbers)
+{
+	uint8_t 	i;
+	uint8_t 	num;
+	uint 		Factor = 1;
+	
+	for(i=0;i<numbers-1;i++)
+	{
+		Factor *= 10;
+	}
+	for(i=0;i<numbers;i++)
+	{
+		num = val / Factor;
+		UART0_Send_Byte((uint8_t)('0' + num));
+		
+		val %= Factor;
+		Factor /= 10;
+	}
+}
+
+void UART0_Send_Int_Hex(uint val, uint8_t numbers, uint8_t Send_0x)
+{
+	uint8_t i;
+	uint8_t Hex_Number;
+
+	if(Send_0x>0)
+	{
+		UART0_SEND_STRING((uint8_t*)"0x");
+	}
+	
+	for(i=0;i<numbers;i++)
+	{
+		Hex_Number = (uint8_t)(val >> ((numbers-i-1) * 4)) & 0x0F;
+		
+		if(Hex_Number < 10)
+			Hex_Number = '0' + Hex_Number;
+		else
+			Hex_Number = 'A' + (Hex_Number - 10);
+		
+		UART0_Send_Byte((uint8_t)Hex_Number);
+	}
+}
+
+uint UART0_Data_Available(void)
+{
+	if(_UART_Buffer.Write >= _UART_Buffer.Read)
+	{
+		return (_UART_Buffer.Write - _UART_Buffer.Read);
+	}
+	else
+	{
+		return ((_UART_Buffer.Write + UART_BUFFER_SIZE) - _UART_Buffer.Read);
+	}
+}
+
+uint8_t	UART0_Get_Byte(void)
+{
+	uint8_t Return_Value = 0;
+	
+	if(UART0_Data_Available() > 0)
+	{
+		Return_Value = _UART_Buffer.Data[_UART_Buffer.Read++];
+		
+		if(_UART_Buffer.Read == UART_BUFFER_SIZE)
+		{
+			_UART_Buffer.Read = 0;
+		}
+	}
+	
+	return Return_Value;
+}
+
+/*******************************************************************
+	Internal Functions
+*******************************************************************/