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WEBENCH® Tools/ADS7953: ADS7953 range from 2.5 to 5V issue

Chandrakant Pal
Intellectual 500 points
Part Number: ADS7953
Other Parts Discussed in Thread: ADS7951,

Tool/software: WEBENCH® Design Tools

Hi,

I am trying to program ADS7951 to auto1 mode with range 2 i.e. 0 to 5 V with following sequence

>> wr 0x4200

>> wr 0x8000 

>> wr 0xFFFF

>> wr 0x2C40

>> wr 0x000 all

But when i vary my potentiometer connected to channel 4 at 2.5V itself the ADC converted value gets set to 4095 whereas it should get set to 2046 i.e half of the 5V count.

I am able to change from 2.5 to 5 V in manual mode by writting 0x1840 in mode register but not able to change in auto mode 1. 

How can i verify that my device has switched to auto mode1?

is the sequence that i am writiing to change to auto mode1 and range 5v right?

Thank you

Regards,

Chandrakant Pal

Thanks

for your replay.

I follow your instruction give the  below instruction to configure the divice

//we dont use GPIO, so omit the instruction of 0x4200  and 0x4001

>> wr 0x8000 // Program Register for Auto-1 Frame 1

>> wr 0xFFFF // Program Register for Auto-1 Frame 2, to select all 16 channles

>> wr 0x2C00 // Enable Auto-1 Mode, counter set to lower programmed channel (Ch1)

>> wr 0x2841 // Stay in Auto-1 Mode, enable increment counter, Range 2 operation and GPIO set as output high

>> wr 0x000 all

  • 0
    TI__Mastermind 25020 points
    Hello,
    The response included within the post, the second set of register commands, seems to be correct.
    The first three commands are to set auto mode and start the sampling at the lowest channel preprogrammed. The second to last command is needed to continue each sample.

    To see if you are in Auto mode 1, is to set the input voltage at each channel at different know voltages
    For example,
    Ch0 = 0.5V
    Ch1 = 1V
    Ch2 = 2V

    and so on. This way, you know if the channels are being sequenced, and if the range is correct.

    Regards
    Cynthia
  • 0 in reply to Cynthia
    TI__Guru**** 180751 points
    Hi Chandrakant,

    Is your issue with the ADS7953 resolved?