Z8F6421PM020SC Datasheet, PDF (19/299 Pages) Zilog, Inc. – High Performance 8-Bit Microcontrollers Z8 Encore-R 64K Series

Z8 Encore!^® 64K Series
Product Specification
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• Example: for the register R1[7:0], R1 is an 8-bit register, R1[7] is the most significant
bit, and R1[0] is the least significant bit.
Braces
The curly braces, { }, indicate a single register or bus created by concatenating some com-
bination of smaller registers, buses, or individual bits.
• Example: the 12-bit register address {0H, RP[7:4], R1[3:0]} is composed of a 4-bit
hexadecimal value (0H) and two 4-bit register values taken from the Register Pointer
(RP) and Working Register R1. 0H is the most significant nibble (4-bit value) of the
12-bit register, and R1[3:0] is the least significant nibble of the 12-bit register.
Parentheses
The parentheses, ( ), indicate an indirect register address lookup.
• Example: (R1) is the memory location referenced by the address contained in the
Working Register R1.
Parentheses/Bracket Combinations
The parentheses, ( ), indicate an indirect register address lookup and the square brackets,
[ ], indicate a register or bus.
• Example: assume PC[15:0] contains the value 1234h. (PC[15:0]) then refers to the
contents of the memory location at address 1234h.
Use of the Words Set, Reset and Clear
The word set implies that a register bit or a condition contains a logical 1. The words reset
or clear imply that a register bit or a condition contains a logical 0. When either of these
terms is followed by a number, the word logical may not be included; however, it is
implied.
Notation for Bits and Similar Registers
A field of bits within a register is designated as: Register[n:n].
• Example: ADDR[15:0] refers to bits 15 through bit 0 of the Address.
Use of the Terms LSB, MSB, lsb, and msb
In this document, the terms LSB and MSB, when appearing in upper case, mean least sig-
nificant byte and most significant byte, respectively. The lowercase forms, lsb and msb,
mean least significant bit and most significant bit, respectively.
Use of Initial Uppercase Letters
Initial uppercase letters designate settings and conditions in general text.
• Example 1: The receiver forces the SCL line to Low.
PS019915-1005
Manual Objectives