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rs232 and 8051 interfacing
im stuck on how i can interface an ADC,DAC and an rs232 to one 8051 microprocessor.can anyone please help?
By Anonymous on 28 June, 2004 - 8:05 am

im stuck on how i can interface an ADC,DAC and an rs232 to one 8051 microprocessor.can anyone please help?

By Anonymous on 30 June, 2004 - 5:22 pm

This is both a simple and complex question. There are many ways you could do it. Is this ALL the I?O you need or do you need to keep free pins for other stuff?

Ultimately it comes down to learning the architecture of the chip you are planning on using. Is this a run of the mill 8051? Zilog makes 8051's with that hardware built in.

So, What chip are you using?
What ADC/DAC chips are you using?
Have you consulted the datasheets?
Have you done a search on Google for "8051 ADC" or 8051 Interface, or projects

Development kits usually provide ADC/DAC and Serial port interfaces. They go for $150 or less.

Myke Predko wrote an excellent book on the 8051. If you plan on doing any more work with that chip, then get the book.. worth the 40 or so dollars. (not that I specifically endorse Myke, the point is, getting A book on the subject will clear most of your questions up)

Hope it helps at least guide you to your answers.

By Dr. Erlich on 14 July, 2004 - 5:29 pm

EID, Corp. is an OEM manufacturer (100% made in U.S.A) for many kinds of electronics kits for industrial and lab use.

For RS232 interface board to the 8051 See the following link:

If you would like to add 12-bits ADC to the 8051 up to 4 channels SE or 2 DIFF--see link:

Best of luck,


By Eugenio Yep on 30 June, 2004 - 5:54 pm

Ugh. It depends on many things. Conversion speed, resolution, etc.

Regarding RS232, the 8051 has a built-in USART, You only need a RS323-TTL buffer like MAX232 and you are done.

With ADC and DACs, I think your best bet is to use converters with SPI or I2C interface and use two or three pins of any 8051 port to implement a SPI interface. You must program the SPI read/write subroutines, but that's rather simple.

Otherwise, you will have to waste a whole 8 bits port, add a latch to sample address and data, add some address decoder, etc, etc, etc.

Take a look on chips like Microchip MCP3001

HTH. Eugenio

By Long, Nguyen on 1 July, 2004 - 1:17 am

you can make an rs232 interface base on 8051 pins.Pins use for rs232 is /RD, /WR, TXD, RXD in port 3.

By Badri Narayanan on 5 October, 2004 - 8:40 pm


what you can do is use DAC chip and Ad7701 or Ad7135 chip for adc.