Embedded Systems Design, 2nd Edition

Embedded processors 25

8 channel 8 bit A/D converter, PWM generator, and synchronous

and asynchronous communications channels (RS232 and SPI). Its

current consumption is low with a typical value of less than 10 mA.

Architecture

The basic processor architecture is similar to that of the 6800

and has two 8 bit accumulators referred to as registers A and B.

They can be concatenated to provide a 16 bit double accumulator

called register D. In addition, there are two 16 bit index registers

X and Y to provide indexing to anywhere within its 64 kbyte

memory map.

Through its 16 bit accumulator, the instruction set can

support several 16 bit commands such as add, ...