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  1. CarbonWerkes

    I2C, debugging problem

    OK, problem seems resolved with more capacitance on SDA. Strange, because the spec says 10pF, and I had tried that very early on- up to 27pF, attempting to emulate the probe's characteristics, with no luck. However, it will start with 100pF on SDA. The silicon engineers are looking into it...
  2. CarbonWerkes

    I2C, debugging problem

    Hi Keith That was my initial thought also- and I found that by touching SDA to ground briefly, that would get things rolling. But, even if the DSO is connected to SDA (i.e. wire soldered to SDA-side of pullup- to the DSO probe), the system will function correctly- where, in theory, the DSO is...
  3. CarbonWerkes

    I2C, debugging problem

    Hi, I have a problem with an I2C bus. For whatever reason, it will not start as it lays on the PCB. However, touching the SDA line with a scope probe kick-starts it, and from that point, it runs as expected even with the probe removed. If the scope probe is physically connected to SDA on system...
  4. CarbonWerkes

    dspic info ??? anywhere ???

    2dye4- Maybe a dead thread- The dsPIC compilers from Mikroelectronika have a Filter Designer tool built in for FIR and IIR types. It has a code generator for their Basic/Pascal/C compilers. It does leverage their Radix libraries, which are not open source, but you can view the generated ASM and...
  5. CarbonWerkes

    Electronic throttle control

    Hi Keith- Logs do sometimes help me (not always!)- but what I didnt post was a log captured later which included the PID resultant, as well as the individual p/i/d components. Really fascinating to see what the controller is doing vs. actual motion. Maybe there are examples of that online, but I...
  6. CarbonWerkes

    Electronic throttle control

    I ran a data log for the pedal vs throttle plate position (hopefully the link for the image works). What is fairly clear is that the PID is tracking very well as long as the plate remains in motion. It seems stiction applies in both directions, despite the presence of the spring return- which...
  7. CarbonWerkes

    Electronic throttle control

    Hi Keith- Presumably, the spring is designed to manage a worst case recoverable scenario, or to at least kill engine power within .1sec of servo loss. It is PID code I wrote- based on the typical variant. There are some limits included for integral error sum, etc, but nothing atypical. It runs...
  8. CarbonWerkes

    Electronic throttle control

    Hi Im looking at a project drive for electronic throttle control (drive by wire). The throttle body, which contains a geared servo and feedback pots, is spring loaded- such that a power failure to the servo will allow the spring to back drive the motor, to close the throttle plate. It seems...
  9. CarbonWerkes

    High Z input stage for ADC

    Hi Gunnar Well, the original design thought was as you suggest here- a high-impedance divider network (approx 1MOhm), into a unity-programmed opamp- perhaps with a small analog filter in between. The SK was only a thought. But Keith brought up good points, in that with a high impedance network...
  10. CarbonWerkes

    High Z input stage for ADC

    Hi Gunnar Thanks for your feedback also. Im curious about the topology you mentioned. Im not familiar with a dual-path filter for a single input, unless that is a hybrid (passive/active). But your message says passive. So is this referencing just a dual input (for the TC as differential) vs a...
  11. CarbonWerkes

    High Z input stage for ADC

    Hi Keith- Thanks very much for your input here- no pun. I do have a topology question remaining. The assumption is that I will use a resistor divider network to scale the 0-15 to 0-3V. My current thinking is that it is beneficial to implement that as the first stage, feeding into a...
  12. CarbonWerkes

    High Z input stage for ADC

    Keith- Sources are automotive sensors- NTC or potentiometer typically. Problem is, I need to tap into existing sensor lines with as little loading as is reasonably possible. If a typical NTC sensor is 500-3K, and Im at 100K on sensor ins, that has more impact than I would like to impose...
  13. CarbonWerkes

    High Z input stage for ADC

    Hi- I have a data logging application which will see 0-15V on some high impedance sources. There will be 12 or more inputs needed- and I have 20+ ADC channels on the microcontroller that will handle the sampling; 12 bit, but that is adequate for my application. To minimize load on the sensor...
  14. CarbonWerkes

    Connector interface, solid state swtiching

    Apparently that just works out- since my calcs for current on a via/post indicate a 60mil throughhole with 2oz copper would get me to 20A. So a bit of a pinch from the 170 into the post, but I can live with that loss. Danonboost, a popular calculator is at...
  15. CarbonWerkes

    Connector interface, solid state swtiching

    Dan/Dan Ipak may be right. I know Dpaks are fine at 20A, Im just not 100% I can get 20A from a solderpad on the source side- that is a small foot on a Dpak. Thats why I was thinking a longer leg extended to a bus bar I can machine. I guess I can design for both, and switch from Dpak to the...
  16. CarbonWerkes

    Connector interface, solid state swtiching

    Hey all- Thanks so much for the very detailed feedback. The real nightmare is, the device will be exposed to nasty vibration- 50-120hz at 2-5g. So Im not sure that a design for an inverter, or even some automotive-rated stuff like power amps, translates well- at least in terms of ability to...
  17. CarbonWerkes

    Connector interface, solid state swtiching

    Hello I have an application where I will need to employ 8-10 low-side mosfets for simple DC power switching- replacing some conventional mechanical switches in an automotive environment. The expected current is 20A at 12V max. Id like to know if anyone has any practical experience with...
  18. CarbonWerkes

    Question, mirroring diagonal slots in SW

    Cheers- this looks like it may work for me. Im not clear as to if the shape of the end very varied assumes the path shape it follows, but even if- I can revisit those truncated ends manually- Kind regards- R
  19. CarbonWerkes

    Question, mirroring diagonal slots in SW

    Hi I saw a chassis (on the site linked)- and was curious about how this diagonal slot pattern would be done in SW. Clearly one method is just the brute force approach, setting up start and end points with the Pattern tool and manually creating/copying sketches. This would allow for the varying...
  20. CarbonWerkes

    adding ESD protection

    IR- In my experience, some newer MCUs do not have protection on analog-capable pins- presumably because of the impact on the ADC. Strange, because most ADC chips seem to have this natively. CM- I would just make sure the MCU option in question is protected fully before you make a decision on...

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