• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 79 subscribers
  • Views 344 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

MSP430FR2512: Lowest Advisable Value for Active Mode Scan Rate_ms?

Jay09
Expert 1030 points

Part Number: MSP430FR2512

Hi All,

Two questions: 

1) What is the lowest/fastest advisable value for the "Active mode Scan Rate ms" parameter? I have noticed there are some misses at 50ms, slightly less at 32, and even less at 20. I have seen examples that use 14 as the parameter. If I want to minimize the possibility of touch misses what is the lowest I can set this parameter? Power consumption is a non-issue and I simply want the best performance. 

2) About the "Inactivity time out" and "Wakeup Interval" parameters on the "Conversion Control" tab of the MCU in Captivate Design Center, if I do not have a "Wake on Proximity Sensor" selected, this parameters are ignored, correct? I currently have "Wake on Proximity Sensor" set to "None."

Thanks! 

  • 0
    Expert 1030 points

    As a followup -- apart from the tuning the sensitivity of the sensor, are there other parameters I can max out to increase the responsiveness of the sensor? In this case I am defining responsiveness as the probability that a given touch event will be detected, keeping all other factors equal. 

    For example, if the scan rate is set to 10 seconds, we will miss a lot of touches, no matter what the conversion control parameters are set to. 

  • 0 in reply to Jay09
    TI__Genius 12615 points

    Hi Jay,

    Yes, the wake on parameters are specific to that sensor. 

    The active mode scan rate is typically 20-40ms for most HMI interfaces (buttons, sliders, etc.), but can go faster, depending on the sensors in the system.

    For example, the fastest is probably 5ms, also if there are 16 electrodes (4 measured in parallel = 4 measurement cycles) and the conversion count = 250 with a conversion clock of 1MHz, then total time measurement time for the 4 cycles is 250 * 1uS * 4 = 1ms.

    However, when connected to the GUI there is communications that happens and the more sensors in the system the more data, which can take another 5ms to send. So setting a sample rate of 5ms with communications will result in an effective sample rate of 10ms.

    BR,

    Leo

**Attention** This is a public forum