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+# Altimeter thingo
+
+## Getting Started
+
+### Dependencies
+
+Bare minimum, you will need:
+
+* make
+* avr-gcc
+* avr-libc
+
+If you want to flash to a real board, you will need:
+
+* avrdude
+
+If you want to simulate a mock/fake version of the software on a virtual AVR
+before flashing, you will need:
+
+* qemu-avr
+
+### Build
+
+	$ make all
+	...
+	$ file build/altimeter*.elf
+	build/altimeter.elf:     ELF 32-bit LSB executable, Atmel AVR 8-bit, version 1 (SYSV), statically linked, with debug_info, not stripped
+	build/altimeter_sim.elf: ELF 32-bit LSB executable, Atmel AVR 8-bit, version 1 (SYSV), statically linked, with debug_info, not stripped
+
+### Run mock/sim build of software in QEMU
+
+The sim build of the software has peripherals mocked out so that the software
+can run in QEMU, where the only peripherals available on the AVR are timers and
+the USART controller.
+
+Thus, the sim build isn't very useful for hacking on I/O driver code, but is
+perfectly fine for higher level logic, such as UI and business logic.
+
+A simulated barometer is provided, which cycles through some preset pressure
+values each time it is asked for pressure. The HD44780 LCD is replaced with a
+thin UART driver instead, which QEMU puts on stdout.
+
+	$ make emu
+
+and from a separate terminal, attach GDB. Optionally set breakpoints before
+unpausing qemu:
+
+	$ make gdb
+	(gdb) cont
+
+You should see some activity in the emulated serial output back on the first
+terminal. Use GDB as normal to play/pause/debug the software. Ctrl+C and k to
+end QEMU.
+
+### Flash good software to chip
+
+With the board reset into programming mode, run avrdude through the makefile
+recipe:
+
+	$ make flash PORT=/dev/ttyACMx
+
+...replacing `/dev/ttyACMx` with the right tty device that shows up when you
+put your microcontroller into programming mode.
+