ECE 4436 Chapter Notes - Chapter 4: Call Stack, Microcontroller, Memory Address

• School: University of Houston
• Department: Electrical and Computer Engineering
• Course: ECE 4436
• Professor: Sira Rao

Document Summary

Learning about a microprocessor: look at block diagram. Accumulators a, b, and d: accumulator a and b 8 bits. Two separate registers: accumulator d 16 bits. Index registers x and y: two 16-bit registers, mainly for indexed addressing. Stack pointer: maintains a program stack in ram. Points to last used memory location for a push operation: decrement when pushing data onto the stack, increment when data are removed or pulled. Program counter: can be used as the base register for certain indexed addressing modes. If carry or borrow occurs: two"s complement overflow (v) If a two"s complement overflow occurs: zero (z) If the most significant bit of the result is set: half-carry (h) If there is a carry or borrow out of bit 3 in an arithmetic operation: interrupt request mask (i) After microcontroller reset, 3 signals determine operation mode: bkgd/modc, pe6/modb and pe5/moda, pp6/romctl.