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วารสารราชบััณฑิิตยสภา
ปีีที่่� ๔๗ ฉบัับัที่่� ๓ กัันยายน–ธัันวาคม ๒๕๖๕
ศาสตราจารย์์กิิตติคุุณ ดร.มงคุล เดชนคุรินทร์ 79

Abstract: Parallel Data Exchange Between Microcontrollers
Professor Dr. Mongkol Dejnakarlntra
Fellow of the Academy of Science,
The Royal Society of Thailand
This article presents a method for exchanging parallel data between the
8088 Microcontroller Board (master board) and the PIC16F627A Microcontroller
Board (slave board). The 8-bit data byte is divided into two groups, each comprising
4-bits and bing sent consecutively from the sending board. The two groups are

combined at the receiving board to retrieve the original data byte.
Regarding hardware, each board uses a data bus with four wires for
sending/receiving data and uses two common signal wires for checking/showing
readiness for data exchange. Concerning software, the author presents two sets
of control programs, one set using polling by each board, the other set using
intemupt on the master board by the slave board. The latter set requires one
more wire for sending the interrupt signal.

The method for data exchange in this article has an advantage, namely,
reduction of data bus wires from eight to four wires, but has a disadvantage
as well, the reduction of data exchange speed to about half of that used with
8-wire data bus. From a test in which the two microcontroller boards were
placed not farther than one foot apart, it was found that the data reaching the
destination board were correctly received, being the same as those having
been sent from the source board.

Keywords: Microcontroller, parallel data, integrated circuit, 8088, 8255, 8259,
PIC16F627A