Timeline for Are there well-established terms for clock sources used with microcontrollers, to distinguish whether microcontroller CLKOUT is required?
Current License: CC BY-SA 4.0
19 events
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| Aug 18, 2021 at 20:13 | comment | added | D.A.S. | This could be that doc , but rather skimpy on details but it does say Class A onlinedocs.microchip.com/pr/… | |
| Aug 18, 2021 at 19:34 | comment | added | jonk | @TonyStewartEE75 The document specially says that it is class-A. It's how it's written. I didn't make it up, despite your continued disagreement here. I'm just offering an experience of mine. That's all. How you take it is up to you. But you can probably just test the idea. It's not hard to do. What I'm saying is verifiable. | |
| Aug 18, 2021 at 19:33 | comment | added | D.A.S. | If it were Class A there would be only a single FET and the internal feedback R would produce Vout = Vgs(th) which is lower than Vdd/2, so the regular usage might produce asymmetric square wave outputs. It should be a high RdsOn unbuffered gate. | |
| Aug 18, 2021 at 19:33 | comment | added | jonk | @JasonS I thought it should have been in the public documentation back then. I said as much to the FAE. But for reasons not entirely clear to either of us, it was available only upon request. (I didn't know to ask for it until the FAE mentioned it, as part of our discussion about reducing power requirements. It was then he said I could ask for it.) | |
| Aug 18, 2021 at 19:30 | comment | added | Jason S | OK, I'm just surprised, because if this were important to Microchip's currently-manufactured products, it should be in public documentation. | |
| Aug 18, 2021 at 19:28 | comment | added | jonk | @JasonS Late 1990's. If I want to spend some time, I could get the exact date. I used the technique and it worked as advertised. Power was about cut in half, as a result. (I was using a Harris oscillator IC at the time which was very very low power.) As Microchip literally builds their chips "forever" in order to support product lifecycles better than any other company I've used, I believe it will still apply to the same parts it addressed then. (The Harris part was the HA7210.) | |
| Aug 18, 2021 at 19:24 | comment | added | Jason S | @jonk when does this internal memo date from? 1995? 2000? 2005? 2010? that may be helpful. I'm skeptical. (disclaimer: I work at Microchip but in the dsPIC division so don't work on 8-bit parts) | |
| Aug 18, 2021 at 19:22 | comment | added | jonk | @TonyStewartEE75 Regardless, I do have the internal memo here. It covers my product of interest at the time, in the PIC16 family. | |
| Aug 18, 2021 at 18:14 | comment | added | D.A.S. | Hmm this one does not support that. ww1.microchip.com/downloads/en/AppNotes/00849a.pdf | |
| Aug 18, 2021 at 18:13 | comment | added | jonk | @TonyStewartEE75 Yes. An internal document I received from a Microchip FAE. It's about five pages in length. | |
| Aug 18, 2021 at 18:12 | comment | added | D.A.S. | @jonk do you have any reference on driving the output?. ASAIK all MCU’s use push-pull CMOS inverters with >=5M internal feedback so they draw current when enabled but not connected to any tank circuit or not oscillating at Vdd/2 from the shootthru limited current. | |
| Aug 18, 2021 at 18:11 | history | edited | Jason S | CC BY-SA 4.0 |
added 42 characters in body
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| Aug 18, 2021 at 18:10 | comment | added | jonk | Just FYI. You get to decide how it matters. And sounds like you have. | |
| Aug 18, 2021 at 18:05 | comment | added | Jason S | @jonk interesting... that may be, but that doesn't affect how I would describe the clock source as one of these two groups of objects | |
| Aug 18, 2021 at 17:40 | review | Close votes | |||
| Sep 2, 2021 at 3:03 | |||||
| Aug 18, 2021 at 17:28 | answer | added | Justme | timeline score: 1 | |
| Aug 18, 2021 at 17:09 | comment | added | jonk | To add to the confusion, there are times when you are using an external oscillator (rectangular can, for example) to drive an MCU where you are supposed to drive the XOUT and not the XIN! (Many Microchip MCUs, for example.) This is because driving the XIN forces the internal class-A inverter amplifier to run hot; but where driving the XOUT allows the internal class-A inverter amplifier to settle on a quiescent state, instead, and thereby greatly reducing power consumption as the inverter is vastly over-powered to deal with idiot-proofing. | |
| Aug 18, 2021 at 17:05 | comment | added | Jason S | related (but not identical) questions: electronics.stackexchange.com/questions/86676/… and electronics.stackexchange.com/questions/36308/… | |
| Aug 18, 2021 at 17:03 | history | asked | Jason S | CC BY-SA 4.0 |