Raspberry Pi "Bare Metal" projects
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references:
	- https://github.com/dwelch67/raspberrypi	
	- bootloader for serial debug https://github.com/jamieiles/rpi-gdb
notes:
	- There are makefiles for both C and Asm frameworks
	- Serial gdb setup (Linux):	
		+ serial connection to ARM target via uart (3 wires tx,rx and gnd)		  
		+ bootloader preloaded in the target board. see "rpi-gdb"
		+ A reset button is nice to have (solder on P6 pins, near HDMI port)
		+ start debug section: "gdb-multiarch -x gdbscript <file.elf>" or "make sdb"
	- jtag debug https://github.com/ddle/RaspberryPi/tree/master/ocd_jtag
		+ "make jdb"
	
1. rpi-gdb: bootloader for serial debug, (updated: also enable jtag port)
	- to use, just copy content of bootloader folder to SD card
	
2. blink: blink the status LED on board.

3. I2C driver in polling mode (Master) 

4. ocd_jtag: bootloader for jtag debugging; config files for ARM-USB-OCD and 
   raspberrypi pi
   
5. timer_interrupt: examples of using interrupt. 
   The serial debug tool still has issues with the current bootloader 
   ( does not response after a breakpoint at interuppt )