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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
