8051 Timing
single byte single cycle instruction
ALE
PSEN#
AD0-AD7
PORT2
4
XTAL1
12
ALE
PSEN#
AD0-AD7
PORT2
single byte single cycle instruction
Standard 8051 Timing
Figure A-1. Comparative Timing of 8051 and Industry Standard 8051
A.4
Software Compatibility
The 8051 core is object code compatible with the industry standard 8051 micro-controller.
That is, object code compiled with an industry standard 8051 compiler or assembler will
execute on the 8051 core and will be functionally equivalent. However, because the 8051 core
uses a different instruction timing than the standard 8051, existing code with timing loops
may require modification.
The “Instruction Set” in Table B-2 on page B-5 lists the number of instruction cycles required
to perform each instruction on the 8051 core. The 8051 instruction cycle timing and number
of instruction cycles required for each instruction are compatible with the Dallas
Semiconductor DS80C320.
EZ-USB TRM v1.9
Appendix A: 8051 Introduction
A - 3
CYPRESS [ CYPRESS ]
