scottcjordan

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About scottcjordan

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  1. I'm using the Digilent Analog Shield on an Arduino Uno, and generating a sine wave on the Shield's AO 0 and a cosine wave on AO 1. These waveforms are generated by cycling through a lookup table and then writing the two AOs in a single library call. The lookup tables are identical save for their 90 degree phase difference. It all starts nicely: But after about an hour of cycling, channel 0 seems to lose a few LSBs: Power cycling the Arduino/Analog Shield returns things to good behavior... for a while. Eventually, AO 0 flatlines. Again, a quick power-cycle fixes matters, so it would appear not to be a heat-related issue. Meanwhile, AO 1 cranks merrily along. ...Any idea what could be going wrong here? I'm fearing a hardware issue in the DAC. Many thanks in advance for any insights or suggestions. --Scott
  2. Thank you, JColvin! As per my updates to my original post, I eventually figured out pins 2 and 5. I have now moved the jumper to IOREF. My software is not yet working but this is one fundamental step towards getting it going. Thanks again for your helpfulness.
  3. Two questions... many thanks in advance: 1) Per https://www.digilentinc.com/Data/Products/TI-ANALOG-SHIELD/AnalogShield_rm_rev3.pdf, ‚Äč"The Analog-to-Digital input converter (ADC) and Digital-to-Analog output converter (DAC) both use the standard Arduino form factor SPI bus pins and use independent chip selects." Question: For those of us developing our own library variants, what are the CS numbers? I am not seeing this documented. Update: From the attached snippet of the schematic, and the likelihood that "CS" = "SYNC" = "SYNCN" = "CSN" = "SS" among other possible nomenclature, is CS for the ADC header pin 3, and CS for the DAC header pin 6? (Also see attached close-up of the Shield's header, which suggests pin 0 on P7 is pin 0 for the Arduino Uno at least. Note the nomenclature is clear on the screen-printing next to the header: ADCCS and DACCS.) Update: Argh! The schematic pin numbering is 1-based; the silk-screened header pin numbers on the Shield are 0-based! ...Really now, this all ought to be documented unambiguously and consistently. SO... are the pin numbers for the chip selects for ADC and DAC 5 and 2, respectively, for the Uno? 2) From the same document, "The jumper needs to be set for whether the connected board uses IOREF, 3V3, or 5V0 for the I/O for the SPI interface." Question: Which setting is needed for which supported Arduino board? That is: For the chipKIT Uno32, the jumper should be ____________For the chipKIT UC32, the jumper should be ____________ For the chipKIT Max32, the jumper should be ____________For the chipKIT WF32, the jumper should be ____________For the Arduino Uno, the jumper should be ____________ As a bonus, suggestions for determining the correct jumper setting from a schematic would be really handy.