I need to build an interface that has 8 ch adc connected to pc.I want to measure voltage between 0-5V with this circuit.I saw one guy built this device with pic14f000.I can't copy device because its mcu is code protected.So i need to build my own device.I need a similar project (schematic, source code of mcu (asm), source code of controller program for pc).Do you have any idea? I really need this project.Thanks.
Try to put an ADC0838 of National Semiconductor. See the next url: **broken link removed**
You can download the source code. In this you have a routine for read ADC0832. The ADC0838 have 8 channels, change the source code, is simple. Only you must add select channel in the routine. If you don´t need high speed is a good choice. Regards. I hope be useful.
Buy yourself a Basic Stamp2 for $40, the ADC0838 for $2.50,
and a serial cable for $2. Load the code at the link above and
you'll have your project done in 10 minutes.
What wrong with PIC 16F877 or comparable? If you alredy know how to program PIC then it's extremely easy to program the ADC in PIC 16F8xx. I had also used MCP3208 from micochip and it's also easy to use with SPI interface.
My undergraduate project was 16 channel analog data
acquisition board. I used PIC16F877 and 2x 4051 8x1 analog
mux for 16 channels but if you need only 8 channels and
0-5V range, it is really easy to implement with only PIC16F877
and MAX232 (for serial port).
What do you need? Schematic, pcb drawings, source code? I
can send word files of my project but unfortunately it is not in
English :-(
hi
TI company have 8 channel 16bit ADC with 8051 cpu inside it with large amount of flash memory and other feartures.you can use it for low speed designs.gain and filter can be programmed by software. and you can detect se/nsor wire break with it.
Thank you for all replies.I am an electronic amateur, so i have no experience about some specific subjects such as adc<->dac.I need everything about this project.For example schematic, firmware for pic (c source code will be appreciated), source code of pc program.I can not find atmel mcu's here.So the most useful mcu is pic16f877 here (I can easily find).Can i have 8 ch adc with this mcu without adc ic? What is the resolution (how many bits?).I want to measure voltage simultaneously.If you have info, please help me
I think that you must first the datasheet of PIC16f877. The ADC have 10 bits (I think). You can use the CCS compiler. This compiler have a wizard. With this you can generate the files with the libraries for ADC for example. You can download this in MCU fileman in this page. You only need free registration. Regards.
Yes, it (16f877) has 8 chs of 10 bits adc. If you don't need very high accuacy then you need no external adc. If you're sure that the input signal will not exceed 5v then I think that you can just connect the adc input with simple rc filters.
If you're not already have other tools please look at
For C compiler : h**p://www.htsoft.com. Lite version is free but you can also find full version somewhere in internet.
For programming tools: h**p://www.ic-prog.com. jdm is simple but I nerver built it myself.
I have ccs, but i even don't play with 877 adc funtion.How will i connect measurement probes and how will i write a code for it? Is there any example projects around here? Thank you.
There is an example file (CCS) in the Examples dir: EX_AD12.C and EX_ADMM.C
The help file wil tell you everything.
If you want 10bit ADC you need to use a voltage reference like the REF02 otherwise the converter gives a very unstable value.
8 bits is no problem (19.5mV/bit)
The channel selector need some time to swich inputpin, and the analog input need to be low impedance or the conversion time becomes longer.
The easiest solution for interfacing eight analog channels to PC is to use a PC data acquisition board for PCI slot (or the old ISA slot). Here is a PC data acquisition board with eight single-ended 12-bit analog input channels for PCI slot:
**broken link removed**
If you got an ISA slot in your PC you can use this one:
**broken link removed**
hi
i m using at8535 mcu .. i have some questions
1) can i connect AGND to a -5 and Aref to +5 for voltage levels starting from -5 to +5
2) what values should be used for the 2 capacitors connected with the crystal( the datasheet does not explain that)
3) i know a bit of assembly and i can learn 8051 assembly but dont know how to use ADC in at8535 mcu