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8051 Architectural Specification and Functional Description
program must also enable the backup power supply to the RST/VPD pin. Applying power to the RST/VPD pin resets the 805 I and retains the internal RAM data valid as the VCC power supply falls below limit. Normal opera- tion resumes when RST/VPD is returned low. Figure 2.56 shows the waveforms for the
2.14 EPROM PROGRAMMING
The 8751 is programmed and the 8051 and 8751 are verified using the
2.15THE 8051 AS AN EVOLUTION OF THE 8048
For every 8048 instruction there is a corresponding 8051 instruction, or in rare cases, a short sequence of instruc- tions. An example of the latter is the adjustment required for the use the 8051 makes of PC- and
8048 and 8049 programs using only the
8048 operations no longer necessary (and invalid) for the
8051 are MOVD, ANLD and ORLD. These instructions control the 8243 I/O expander chip. Since the 8051 uses a shift register for
necessary) as the s.ystem clock. The 64K contiguous memory preempts the need for the SEL MBi instructions. The SEL RBi instructions are preempted by instructions that manipulate the PSW.
2.16DEVELOPMENT SYSTEM AND SOFTWARE SUPPORT
The 8051 is supported by a total range of Intel develop- ment tools. This broad range of support shortens the product development cycle and thus brings the product to market sooner.
•ASM51 Absolute macro assembler for the 8051.
•CONV51 8048 assembly language source code to 8051 assembly source code conversion program.
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•8051 Workshop.
8051 Software Development Package (ASM51 and CONV51)
The 8051 software development package provides de-
. velopment system support for the powerful 8051 family of single chip microcomputers. The package contains a symbolic macro assembler and 8.048 to 8051 source code converter. This
8051 Macro Assembler (ASM51)
The 8051 macro assembler translates symbolic 8051 as- sembly language instructions into machine exectuable object code. These assembly language mnemonics are easier to program and are more readable than binary or hexidecimal machine instructions. Also, by allowing the programmer to give symbolic names to memory loca- tions rather than absolute addresses, software design and debug are performed more quickly and reliably.
ASM51 provides symbolic access for the many useful addressing methods in the 8051 architecture. These features include referencing bit and byte locations, and provide
The assembler supports macro definitions and calls. This provides a convenient means of programming a frequent- ly used code sequence only once. The assembler also provides conditional assembly capabilities. Cross refer- encing is provided in the symbol table listing, which shows the user the lines in which each symbol was de- fined and referenced.
If an 8051 program contains errors, the assembler pro- vides a comprehensive set of error diagnostics, which are
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