---------- Forwarded message ---------- From: antonio rosa <antoniorosarodrig...@gmail.com> Date: 2011/8/30 Subject: Re: [Tinyos-help] Problems with ADC to perform two consecutive readings on IRIS Mote To: Janos Sallai <sal...@isis.vanderbilt.edu>
Hi Janos, I understand you. I use the ReadNow interface of the AdcReadNowClient component, but the source of the problem is that when I do two consecutive reading of diferents channels of ADC, if the first reading is a channel different of ATM128_ADC_SNGL_1_23 channel (internal voltage on IRIS) the value is correct, and the seconds readings is the ATM128_ADC_SNGL_1_23 channel the value is wrong. Also, If I read only the ATM128_ADC_SNGL_1_23 channel the value is correct, but when I read other channel in the same application, the read of ATM128_ADC_SNGL_1_23 channel is wrong. I have guess that when you read the internal voltage of Atmega1281, the first time the reading is wrong, the second time the reading si correct. In short, if you make several readings of different ADC channels, you must do two consecutive read internal voltage channel and discard the first reading because it is wrong, yet the latter is correct. read the ATM128_ADC_SNGL_1_23 channel, 2011/8/30 Janos Sallai <sal...@isis.vanderbilt.edu> > Antonio, > > I have a guess what can be wrong. I assume you're using either the > Atm128AdcSingle or Atm128AdcMultiple interface. While the dataReady > event is slightly different in these two interfaces, in each cases it > has a bool parameter, not an error_t. Notice that the value of the > SUCCESS constant is 0, which happens to be the value of FALSE. That > is, when you think that the dataReady event came back with a SUCCESS, > it is, in fact, coming back with a FALSE. > > Let me know if this was the issue. > > Janos > > On Mon, Aug 29, 2011 at 7:37 AM, antonio rosa > <antoniorosarodrig...@gmail.com> wrote: > > Hello all, > > I have a problem with the IRIS platform. When I do readings of different > > channels of ADC reading the microcontroller's internal voltage (channel > > ATM128_ADC_SNGL_1_23) the event (dataReady) is SUCCESS but the reading > > (data) is erroneous. I have cheked that if I make two consecutive > readings > > of the same channel ADC, everything is correct. However, if I previously > do > > a reading from a channel different than used to read the internal > voltage > > and then read channel internal voltage, the value returned by the adc is > > wrong (superior the voltage of the batteries). > > > > In TinyOS.1.x with Moteworks, doesn't ocurrs this problem. I have > reviewed > > the TinyOS-2 driver 1.1 for the module Adc Atmega1281, and I think the > > problem may be related to reading different channels that aren't managed > > properly. > > > > Regards, Antonio Rosa. > > _______________________________________________ > > Tinyos-help mailing list > > Tinyos-help@millennium.berkeley.edu > > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > > >
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