Thread: tohmm TOH Multimeter
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kimmoli is offline kimmoli
2014-04-09 , 08:12
Posts: 562 | Thanked: 2,744 times | Joined on Dec 2013 @ Espoo, Finland
#7
Originally Posted by juiceme View Post
Hmmh, why not an oscilloscope, or at least a possibility to plot voltage changes over time...
See specs ^^
Note; This is not a oscilloscope. That toh will be done later with its own micro to buffer/preprocess samples.

Originally Posted by juiceme View Post
Usually multimeter functionality is implemented by sampling the voltage in analog hold, and then measuring the time differential when bleeding it off through a known resistance. (this allows for really accurate measurement with no A/D converter needed, and is easy/cheap to implement with a dedicated chip).
For me that is also an A/D converter

However with a real fast-sampling A/D conversion it woud be possible to get the waveform plot too.[/QUOTE]
Maximum samplerate with A/D converter selected (atm) is 860 sps.

400kHz I2C limits samplerate to about 7ksps, (at 16bits) but when taking IOCTL etc into account, maybe something like 10 sps in realtime could be doable without buffering...
(if taking samples in background for a short period of time, 860sps is doable)
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