From 9da24b9857e2654c4101024086f8c84e7c74e7e1 Mon Sep 17 00:00:00 2001
From: FreeArtMan <dos21h@gmail.com>
Date: Thu, 25 Aug 2022 13:16:37 +0100
Subject: Added avr8

---
 md/notes/undefined_c/titles.md | 62 +++++++++++++++++++++++++++++++-----------
 1 file changed, 46 insertions(+), 16 deletions(-)

diff --git a/md/notes/undefined_c/titles.md b/md/notes/undefined_c/titles.md
index 85a8456..a383b82 100644
--- a/md/notes/undefined_c/titles.md
+++ b/md/notes/undefined_c/titles.md
@@ -1631,18 +1631,12 @@ rustc main.rs -l lib -L . -o hello -C link-arg="-Wl,-rpath=./"
 
 ## Multiplatform
 
-### Cross compile
-
-
-
-
-
 ### Different flags
 
-
 ### Check architecture
 
 
+
 ### AArch64
 
 https://snapshots.linaro.org/gnu-toolchain/13.0-2022.08-1/aarch64-linux-gnu/
@@ -1694,22 +1688,58 @@ Hello world arm64
 
 ### AVR8
 
+AVR is 8bit CPU that is quite popular for hobbiest. As baremetal device its doesnt have full libc support,
+and needs some setup before its possible to do basics things with it.
 
-### Emscripten
+__avr_echo.c__
+```c
+#include <avr/io.h>
 
-[/writeup/web_assembly_sdl_example.md](/writeup/web_assembly_sdl_example.md)
+#define FOSC 16000000UL
+#define BAUD 9600
+#define MYUBRR FOSC/16/BAUD-1
 
-#### Embed in JS
+void USART_Init( unsigned int ubrr)
+{
+	UBRRH = (unsigned char)(ubrr>>8);
+	UBRRL = (unsigned char)ubrr;
+	UCSRB = (1<<RXEN)|(1<<TXEN);
+	UCSRC = (1<<URSEL)|(1<<USBS)|(3<<UCSZ0);
+}
 
+int main()
+{
+	char c;
+	USART_Init( MYUBRR );
+	while(1)
+	{
+		while ( !(UCSRA & (1<<RXC))){};
+		c = UDR;
+		while (!(UCSRA & (1<<UDRE))){};
+		UDR = c;
+	}
+	return 0;
+}
+```
+
+```
+avr-gcc avr_echo.c -mmcu=atmega16 -Wall -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -o avr_echo.out
+```
+
+Next steps woule be to programm it, in case you have ISPv2 programmer and ATmega16 chip
 
+```bash
+avr-objdump -s --disassemble avr_echo.out > avr_echo.s
+avr-objcopy -j .text -O ihex avr_echo.out avr_echo.hex
+avrdude -pm16 -cavrispv2 -Pusb -U flash:w:avr_echo.hex
+```
+
+### Emscripten
 
-## Graphics
+[/writeup/web_assembly_sdl_example.md](/writeup/web_assembly_sdl_example.md)
+
+#### Embed in JS
 
-### SDL2
-### GTK
-### OpenGL
-### Shaders
-### Generate image
 
 
 
-- 
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