8051 Development Board, Rev 4
The 8051 development board provides an easy-to-use and low-cost way to develop
your 8051 based microcontroller projects, without purchasing any other
special equipment, such as IC programmers or emulators. All required
software is available as a free download, including a C compiler!
- Standard 87C52 CPU clocked at 22.1184 MHz
- 50 I/O lines!! All I/O lines are clearly labeled and available
at the edge of the prototype construction area.
- 32k SRAM, program variables and code (24k usable for code download)
- 30k Flash ROM, non-volatile program storage and data logging
- High speed baud rates: 115200, 75600, 38400, etc. All standard
baud rates are supported (except 300 baud)
- Display port, works with standard character-based LCDs. A 16x2 display
will be available from PJRC (see photo below)
- Eight LEDs, controlled by 8 dedicated I/O lines (not shared with the
50 I/O lines)
- Bus expansion with 4 chip select signals, for adding UARTs,
A/D converters and other bus-based peripheral chips.
- Unregulated, polarity-protected DC voltage input with 2 position
- PAULMON2 monitor for easy code development without additional
- DC Voltage, 8 to 15 volts (regulated), 50 mA or 300 mA with LCD.
- PC Computer With Serial Port, Linux or Microsoft Windows 95-OSR2, 98, 98SE, NT4, 2000.
- Assembler or Compiler, usually AS31 or SDCC
- Terminal Emulation Program, eg Hyperterminal (windows), Minicom (linux)
- Text Editor Program, eg Notepad, Vi, Emacs
- Standard 9 pin serial cable (straight through, not null-modem!)
LCD Display Port
The 8051 development board's LCD port provides the 14 signals
needed for standard character based LCD modules. A 16x2 display
is available from PJRC:
This is a backlight display with transmissive LCD. In bright lighting
(as this photo) the characters appear as highly readable green against
a dark blue background. In darkness, the characters are bright green
against the darker background (which does pass a small amount of the
backlight, yet still remains much darker than the displayed characters).
Like all character modules, eight custom (graphic) characters may be
downloaded to the display, in addition to the build-in character font.
larger copy of this photo (110k) is
available for your viewing pleasure.
Demo Programs Source Code
There four programs are loaded into the flash rom memory on
as part of the testing done by PJRC.
These assembly language files contain ".org" directives which place
the code in Flash ROM, from F000 to F7FF. When you modify these
programs, you will need to erase the originals in the Flash ROM
before downloading, or change them to be built into RAM or a different
location in the Flash ROM.
See the memory map page for details.
This is the complete monitor code provided on the board:
- paulmon21.asm - PAULMON 2.1 Configured For This REV 4 Board
- extra.asm - Disassembler, Memory Editor and Single-Step Utilities
- pm21_2f4.hex - Intel Hex For 87C52 (these two compiled and merged together)