ADC 12 Bit 3202-B ADC

Cenlasoft · 2009-10-26 15:26

Hello,
I downloaded the 12 bit ADC object and tried the code. I don't have a joystick, but I used a 10k pot on channel 0 with 3.3 v and ground. (wiper to channel 0). I commented out the average line and I only get the number 24 as a result. I looked at the datasheet and tried to understand the configuration of %0011 in the MCP3202.start function. Can someone explain how to get a single channel (0) running for now? Can I use a pot to test the object?
Thanks,
Curtis

StefanL38 · 2009-10-26 18:14

I compared the datasheets of the MCP308 with the MCP3202

there seems to be a slight difference in the serial communication

see attached pictures

dataheets:
MCP3202

MCP3208

best regards

Stefan

Cenlasoft · 2009-10-26 18:41

Hello,
Thanks for the help.
I found the problem, the pins had to be P0, P1, and P2. I guess they are SPI pins only. Now I will see if I can change the %0011 to where I can use only channel 0.
Thanks,
Curtis

StefanL38 · 2009-10-26 21:13

No that is surely NOT the problem.
ALL Propeller-IO-pins are general-purpose IO-PINS

The Pins 30,31 and wich are used for download programs and Pins 28,29 wich are connected to the EEPROM
are a little bit different but just because some pull-up-resistor are connected to the IO-pins.

If you take a naked propeller-chip all 32-IO-pins work the exact same way

So maybe something inside the code was not matching. From a hardware-sight all IO-pins are the same

best regards

Stefan

John Abshier · 2009-10-26 21:41

I had problems with this driver and posted updated code. I did not update the object exchange since it was not my object. Here is a link
http://forums.parallax.com/forums/default.aspx?f=25&m=387025

John Abshier

Cenlasoft · 2009-10-29 02:08

Thanks John,
I'll try it and let you know.
Curtis

Cenlasoft · 2009-10-31 21:30

John,

Your modifications to the object allowed the use of pins other than 0,1,and 2. I still cannot get it to work on two channels. It works for either channel but gives me an (11) for one channel for a 2 channel configuration.

Great work,

Curtis

Harprit · 2009-11-07 21:25

Take a look at the SPIN code I posted for reading the 3202
in Propeller Object exchange. Search 3202.
It goes over the communications a bit at a time and might
help you understand what is going on.
Reading two channels should be no harder than reading one
channel. Try reading them one at a time first back and
forth and get that going first.

Harprit

Cenlasoft · 2009-11-08 16:25

Thanks Harprit,

I will look at it. The original object that I downloaded worked great on both channels, but it had to use pins 0,1, and 2. The object·I got from·John Abshier worked on any pin, but I could not get it to work with both channels. The 3202 is a great IC and would like to use it in my projects with one or two channels.

Thanks,

Curtis

John Abshier · 2009-11-08 17:12

I just checked out the chip and it worked with both channels.· Attached is complete project with driver and test program.· Inputs were connected to the pots on the Professional Development Board.

John Abshier

Cenlasoft · 2009-11-09 02:27

Thanks John,
It works, but can I change the PLL4X ?
Curtis

John Abshier · 2009-11-09 05:28

I had not noticed the PLL4X. PLL16X has problems. I think PLL8X will work. I tried a quick fix without looking at the chip data sheet but it didn't work all the time. The error I get is a reading off by a factor of 10 or 100. For example if the value most of the time is 3057, there will occasionally be a reading of 305 or 30. Sorry.

John Abshier

John Abshier · 2009-11-09 16:29

I think the last code I attached works at 16X. I think the problem I was seeing was caused by the latency setting of my USB port. Changing it from 16 to 1 seems to have fixed the problem. Give it a try at 16X and let me know if it works.

John Abshier

Cenlasoft · 2009-11-09 17:27

Thanks John.

I'll try it this afternoon and I will let you know.

Curtis

Bobb Fwed · 2009-11-09 23:15

Try the driver I have in my signature (below). It works on 8, 4, 2, and 1 channel Microchip ADCs in both 10- and 12-bit.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
April, 2008: when I discovered the answers to all my micro-computational-botherations!

Some of my objects:
MCP3X0X ADC Driver - Programmable Schmitt inputs, frequency reading, and more!
Simple Propeller-based Database - Making life easier and more readable for all your EEPROM storage needs.
String Manipulation Library - Don't allow strings to be the bane of the Propeller, bend them to your will!

ADC 12 Bit 3202-B ADC

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