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adc16_set_channel |
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void adc16_set_channel ( unsigned short int port, unsigned short int channel, unsigned short int resolution, unsigned short int single_ended, unsigned short int filter_factor);
You should call this routine once for each channel that you would like to take readings from. You can do this any time after calling adc16_driver_open. It is permissible to change the settings as and when required. The fewer channels are selected, the more frequently these channels will be updated: it takes about 1 second per active channel. Arguments: port specifies which serial port you wish to define a channel for. channel specifies which channel you want to set the details for. It should be 1..8 for single-ended or 1,3,5,7 for differential.
The resolution specifies the conversion accuracy: it should be between 8 bits and 16 bits. See appendix A for the conversion times at each resolution. single_ended specifies whether to use the channel as a single-ended input, or to use the channel together with the next channel as a differential input. single_ended = FALSE is valid only for odd-numbered channels. filter_factor controls the time constant of the filter. Each time the driver takes a reading from this channel, it updates the filtered value by adding a proportion of the difference between the measured and filtered values. The filter_factor sets the proportion that is added.
The filter_factor must be between 1 and 100. A filter_factor of 1 means add all of the difference (effectively no filtering) and 100 means add 1/100 of the difference (very slow filtering). A factor of 10 gives a time constant of about a minute when all channels are selected. The effective resolution is increased by the filter_factor, and the noise floor is reduced by approximately the square root of the filter_factor.
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