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Professional Development Board (PDB) and the Max1270. — Parallax Forums

Professional Development Board (PDB) and the Max1270.

knightofoldcodeknightofoldcode Posts: 233
edited 2006-10-12 23:55 in BASIC Stamp
Group,

I'm trying to build a circuit to test and become more familiar with the Max1270 chip.

Before I start to experiment, I like to make sure everything is working, and so far I can't get the Max1270 to work. I've followed the instructions on the Nuts And Volts issue 105 to the letter, but I still can't seem to get it to work. For one I found a typo on the schematic on figure 105.5. I believe the pin numbers for the "REF" and "REFADJ" pins of the Max1270 are incorrectly labeled. Also, the figure 105.5 does not mention needing a 5v+ supply for the logic of hte chip, Pin1.

After I have added in the power pin on pin1, and followed the figure 105.5, I still can't get my Max1270 to work. The code I am using is PURE stock code from the 105 nuts and volts. I change NOTHING in the code. On my PDB the Max1270's logic pins are connected as follows:


Max1270 Pin 6 (ADC_CS) is connected to my Basic Stamp pin 3.
Max1270 Pin 5 (CLOCK) is connected to my Basic Stamp pin 0.
Max1270 Pin 7 (ADC_DI) is connected to my Basic Stamp pin 5.
Max1270 Pin 10 (ADC_DO) is connected to my Basic Stamp pin 4.

Which as far as I can tell, is the way it's hooked up on the Stamp PLC.

What am I doing wrong? It's got to be a hardware issue. Is there any connection difference on the shared clock line? I just did a straight wire connection from the Max1270's Pin 5 (CLOCK) line directly to the Stamps Pin 0, should there be some kind of pull up or down, or any form of a resistor on this line?

BTW, the DEBUG output, shows all channels as 0.000 not matter what is done. Yes, I have the channel hooked up properly, I have a wire going directly from VDD (5V+) directly to the input of the channel. It's a regulated 5V+ directly from the onboard 5V+ regulator.

Much thanx in advance,
Knight.

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Comments

  • knightofoldcodeknightofoldcode Posts: 233
    edited 2006-10-12 20:56
    I am certain it's not the chip, or the BS. I have swapped out the Max1270, and the Basic Stamp with a BS2P40, and a BS2, with the same results.

    Is there anyway I can get ahold of a Stamp PLC schematic?

    Knight.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-=-=-=-=-=-=-=-=-=-=-=-
    This message transmitted with 100% recycled electrons.
    -=-=-=-=-=-
    Gravity doesn't exist. The Earth sucks.
    -=-=-=-=-=-
    Make a man a fire, and he will be warm for the night.
    Light the man on fire, and he will be warm for the rest of his life.
    -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-=-=-=-=-=-=-=-=-=-=-=-
  • metron9metron9 Posts: 1,100
    edited 2006-10-12 22:56
    That Column shows pins 5 and 6 as being sclk and clk and ref and refadj They also show pin16 VDD and ch3 pin16 and no pin1 on the schematic.

    Check your connections using data on page 8 of this datasheet.

    http://datasheets.maxim-ic.com/en/ds/MAX1270-MAX1271B.pdf#search="max1270"

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    Think outside the BOX!
  • knightofoldcodeknightofoldcode Posts: 233
    edited 2006-10-12 23:55
    metron9 said...
    That Column shows pins 5 and 6 as being sclk and clk and ref and refadj They also show pin16 VDD and ch3 pin16 and no pin1 on the schematic.

    Check your connections using data on page 8 of this datasheet.

    http://datasheets.maxim-ic.com/en/ds/MAX1270-MAX1271B.pdf#search="max1270"

    I checked it all the exact same way I've always checked them.

    However, while I was checking your suggestion, I found my problem. Then Stamp PLC framework code has the following:

    AdcDo           PIN     5                       ' ADC data out (to)
    AdcDi           PIN     4                       ' ADC data in (from)
    
    



    I incorrectly thought that this means that the Pin 4 goes to the ADC's Input pin, however it's not, it's reversed. So the schematic on figure 105.5 is HORRIBLY wrong.

    The data pins should be reversed on the schematic, and the power pin is ommited. Also, as you have pointed there are other flaws with the schematic.

    I've never seen Jon get the schematic so bad. I've seen him miss one or two things, but there is alot of messed up parts. I guess Jon just had too much programming on his mind that night. [noparse]:D[/noparse]

    It didn't damage anything, and I figured it out, so I'm happy.

    Much thanx for the help, Metron.

    Knight.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-=-=-=-=-=-=-=-=-=-=-=-
    This message transmitted with 100% recycled electrons.
    -=-=-=-=-=-
    Gravity doesn't exist. The Earth sucks.
    -=-=-=-=-=-
    Make a man a fire, and he will be warm for the night.
    Light the man on fire, and he will be warm for the rest of his life.
    -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=--=-=-=-=-=-=-=-=-=-=-=-=-
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