I would spend a chapter on the bootloader, and just putting some code on a chip. Basically talking to the chip, and flash an LED. Great start, minimal code.

I would ignore writing anything on each command, as a search or reading the manual will work everytime.

Keep in mind that a chip is all about IO. Spend a lot of time on this (like the rest of the book). Digital input, analog input (linear and logarithmic). Maybe a temperature sensor (thermisistor). Bluetooth, 802.11a/b/g, ethernet, RS232 (both internal and Max232a, etc). Output to LED, LCD, Touch screen, data logger on chip and external stuff like SD card, eeprom, X10, etc.

If you had projects like home automation, and logging, maybe a thermostat, you will sell a bunch of books, and I'd buy one. If you went into commands I'm out, a waste of my time and money. Don't teach logic, that can be obtained anywhere. Fundamental circuits are OK though because there are way more programmers than there are circuit designers.

Always explain why you are selecting a command over another one, or a specific circuit.