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RM57L843 ADC Speed

Phil Nguyen
Prodigy 170 points
Other Parts Discussed in Thread: HALCOGEN

Hi,

Anyone please let me know the maximum ADC MSPS on the RM57Lx devices?

C2000 MCU stated quite clear the maximum ADC rate is 14 MSPS.

I can not find identical information for the RM57Lx devices, which is a bit annoying.

Many thanks,

Phi

  • 0
    TI__Guru**** 463421 points
    Hello,
    I will move your post to the Hercules forums, where the experts there can help you best.

    Thanks
    ki
  • 0 in reply to Ki
    TI__Guru**** 190746 points
    Hi Phil,
    You should be able to achieve 1.5MSPS for ADC.
  • 0 in reply to Charles Tsai
    Prodigy 170 points

    Thank you for the information, and

    a) Where do you get the information from, or you just work it out yourself from the information provided in the datasheet (page 172)? I found it stated that the total time is 0.6us in 12bit mode, and 0.53us in 10-bit mode, but not clear is that the time taken for all channels, or only one channel. If it is one channel, then how the time will be added up if I scan for example 10 channels?

    b) Do you know why this new generation device has such a slow ADC module engine?

    Cheers,

    Phil

  • 0 in reply to Phil Nguyen
    TI__Guru**** 190746 points

    Hi Phil,

     Yes, you can use the datasheet total sample/hold and conversion time to to calculate the maximum samples per second. Below is what I use the derived the maximum using HalCoGen. With 33.33 ns (this is the maximum ADC clock frequency) of cycle time, the sample time is about 233ns and the conversion time is 433ns. If you add them up it is about 666ns for one channel conversion. This is how I derive with 1.5MSPS. Note that this is the theoretical number and you may not achieve this speed with your clock setup. Note that the ADCLK is prescaled from VCLK. In order to achieve ADCLK=30MHz you will need to scale the VCLK, HCLK and GCLK accordingly.