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80C39-8749 MCS-48 Examples and code
The Early Microcontroller :

80C39 is a CMOS Version of 8048 the one that preceded 8031-8051. MCS48 is the set for that. Here are some example projects for 80C39-8748-8749 microcontroller. MCS51 is the set for 80C31 and 8051.

Voltage to Frequency Converter AD Interface is the analog front end of this instrument. Uses a LM331 VCO. The Signal conditioning too is integrated in this circuit.

A complete two set point Process Controller using 80C39. 8048 and its mnemonic code set MCS-48, is
the first popular Microcontroller. This had no Serial Port and limited memory. This code was written by me, and it works ok. Even though these chips are obsolete, the interfacing circuit and code can help learn some concepts.
80C39 and MCS48 based Process Controller is the main circuit that has the LED 7 segment display for output and push keys for input. The old form of Human Machine Interface - HMI.

This was supposed to have Analog in and Analog out. Some parts of the circuit may be in the 80C51 page. This has ramp-up and ramp-down settings for the Increment and Decrement buttons. This helps setting setpoint quickly. There is also debouncing for the pushbutton.

The MCS-48 microcontroller (C) series, Intel's first microcontroller, was originally released in 1976. Its first members were 8048, 8035 and 8748. Initially this family was produced using NMOS-technology, in the early 1980s it became available in CMOS-technology.

Digital to Analog Converter with uC Watchdog is the front end and an external  hardware watchdog of an early kind. These are simple but robust circuits and worked well in noisy environments.

The Intel 8748 has on-chip clock oscillator, 2 8-bit timers, 27 I/O ports, 64 bytes of RAM and 1 KB of EPROM. A version with 2 KB EPROM and 128 bytes RAM was also available under the 8749 number.

Learn more about current 8031 tools here - Rigel - Ebedded Controllers and Software

8749 MCS-48

Process Controller code here 80C39 Code for MCS48
The circuit for these are on this page along with other circuits. Read Code in MCS-48 Spreadsheet

Single Components MCS-48 System

8-bit timer/event counter,  Two interrupts,  Single 5-volt supply,  Three 8-bit bi-directional I/O ports,  Up to 256 bytes of data memory, Up to 4K of program memory.

Single Components MCS-48

This may be difficult to put together now. But the code and hardware is near compatible to 8051 uC. Now there are may types of ADC and uC.






delabs Technologies

20th Apr 2020


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