Problems with MCP3202 driver

John Abshier

I tried to use Chip's MCP3202 driver with ViewPort and ViewPort would not start.· I found a problem with the MCP3202 driver.· The assembly code reads 5 longs for parameters but the Spin code only sets up 4 longs.· If I comment out this code, ViewPort works, but DAC functionality is lost.

{                        call    #param                  'setup DAC configuration
        if_c            or      dira,t2
        if_c            movs    ctra,t3
        if_c            movi    ctra,#%00110_000
                        shr     t3,#8
                        call    #param2
        if_c            or      dira,t2
        if_c            movs    ctrb,t3
        if_c            movi    ctrb,#%00110_000        }

John Abshier

Hanno

Thanks for posting John.
I believe what's going on is that DIRA is set to a value that affects pins 30 and 31- which ViewPort requires for serial communication. This is the beauty of the Propeller- programs running in different cogs really shouldn't affect each other- apart from shared resources like global memory and the IO pins.

The most common problems users have with ViewPort are:
- not setting the timing constants correctly- this causes the conduit to send data at an incorrect baud rate
- using pins 30 and/or 31 in their own program- this prevents the conduit from sending/receiving data.
- not using the vp.share statement- so the conduit never runs

Best thing is to give the included tutorials a try and maybe even explore that book written by that spanish guy- manuel? Manual?
Hanno

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Download a free trial of ViewPort- the premier visual debugger for the Propeller
Includes full debugger, simulated instruments, fuzzy logic, and OpenCV for computer vision. Now a Parallax Product!

John Abshier

Hano, I am sure that dira is getting clobbered when the MCP3202 driver reads the 5 parameter. Since my present need does not require DAC, commenting out the DAC setup is a quick fix. When I need DAC as well as ADC, I will do a proper fix if Chip has not already done so. I am going to visit the grandkids so I won't be doing anything with the Propeller for 3 or 4 days.

John Abshier

Hanno

Enjoy the grandkids!
Hanno

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Download a free trial of ViewPort- the premier visual debugger for the Propeller
Includes full debugger, simulated instruments, fuzzy logic, and OpenCV for computer vision. Now a Parallax Product!