Book on Atmel AVR

The Arduino platform is an excellent introduction for the novice to the microcontroller. But at some point, you might feel like digging deeper into the subject. You might have seen direct port manipulation code or code that uses interrupts, and wondered where you could read more about this stuff. I recently purchased Barnett's book above, and the second chapter titled "The Atmel RISC Processors" goes into details of the AVR architecture, timers, interrupts, communication protocols, etc. I highly recommend this book. Although the Indian edition shown is the first edition, it still gives a comprehensive, relevant introduction to the subject. It is available at the IISC bookstore (TATA) in Bangalore for about Rs. 320.