Digtal ports replacing ADC

[ravit245]

Hello,

In my microcontroller ,there is no ADC available.i have digital ports.I want to use the digital ports for replacing ADC.
Is it possible?

Regards
Ravi

 

[nikhilt007]

You have to use external Adc converter

 

[themask]

ADC0804 is the probably the most common general purpose A/D chip.

But using an external A/D is really unnecessary.

just switch your microcontroller to a variant that a built-in A/D module

 

[ravit245]

Thanks for your valuable inputs.
But it is my mistake I did nt give the complete details.
actually It is a very big project,all the ADCs in the uC were used .now no ADC left for the present requirement.Now I have left only choice to use digital ports in uC.It is not possible to change the uC and add another ADC.
Please suggest me is there any way to use this digital ports for replacing ADC.


Thanks & Regards
Ravi

 

[andre_luis]

You can employ an serial I2C small package A/D IC, which requires just 2 digital I/O pins.
In having another I2C devices already being used, will not require additional ports, due you can connect at its existing bus.


+++

 

[betwixt]

Or you can use a digital port as an output, connect it to an external DAC and a comparator then read back the comparator output. In other words, create your own analog voltage from the data in the port and compare it to the voltage you are measuring so see when they match. It is easy and fairly quick if you use sucessive approximation techniques.

Brian.

 

[pjmelect]

Instead of a ADC0804 try a ADC0809, I sell them very cheaply on eBay (from Sunday evening) for only 99p for two.