@Paul - I have no idea of the sense of scale and the relative times taken. If I were to hang another HV driver on the chain with associated electronics to switch the HV, is there going to be enough time to do the following:
Set the bits for the segments required- I add this step just in case any settling time might be be required Set the bits for the segments required and the anode(s) on Wait for 400us (typical on time for the panaplex segments I have in mind Set the digits and anode(s) off again Loop to the next set of digits With 12 individual anodes - there would be 12 passes - one for each anode that needed to be switched on If I used 2 drivers (using 3 x 16 bits for cathodes, I could use bits from the remaining 16 to control the anodes. Thus there would be only 3 passes. Please stop me when I've gone off the scent (still mid-covid) :-( In Summary: Using the HV55xx for cathodes AND anodes Given i want 12 characters: with 1 driver I have 16 segments and 16 spare for the 12 anodes - easy but slowest with 2 drivers I have 3 lots of 16 segments and then group the displays into lumps of 4 (12 characters/3) and still have 16 bits to control the anodes, of which there will now only be 3) Am I anywhere near close with the driver split and the pseudocode for the ISR? I was thinking that there should be some uS delays either before and/or after lighting the segments - Richard On Wednesday, 1 November 2023 at 15:01:20 UTC Richard Scales wrote: > @David - many thanks for that caution though there will not be (nor ever > will there be!) any LEDS for this project! > @Pauld - thank you - I had thought of that but I was endeavouring to keep > the code inside the ISR to an absolute minimum so thought that it would be > best handled outside of it and hence separate from the HV chain. Using > SPI.Transfer to send 32, 64 or 96 bits - I guess it all happens fairly > quickly! > @Benoit - I will look at that - ESP32 - another bridge thus far uncrossed! > - Richard > > > On Wednesday, 1 November 2023 at 14:54:53 UTC Benoit Tourret wrote: > >> Hello, >> >> if an ESP8266 is not enough powerful, the ESP32 will do the job. >> the ESP_WROVER can be a good platfom. >> you should have a look to Mose's work on https://neonixie.com/Z57XM6DV2/ >> the code is a bit "strong" as it can be used both on an 6 IV-9 clock and >> a more traditional 6 digits Z57, superb clocks, all they need is >> addressable LEDs for a more colorful background. and deactivable. >> the BH1750 luxmeter does a great job and is more sensible than a standard >> photoresistor. >> >> Le mercredi 1 novembre 2023 à 14:38:44 UTC+1, David Pye a écrit : >> >>> Hi, >>> >>> I offer you one caution with the ESP8266 boards - almost everything is >>> implemented in the libraries in software rather than onchip hw. >>> >>> That means doing things like updating addressable LEDs can cause the >>> multiplexing to glitch slightly because of the need to send LED data at >>> strict timings. (Or, if you sacrifice led timings to run your multiplex >>> interrupt routine, it can glitch the LEDs. ). Chips which have DMA/more >>> complex peripherals might avoid this. >>> >>> You might get away with it with certain combinations of things but it >>> was a bit of a pain for me. >>> >>> David >>> >>> On Wed, 1 Nov 2023, 11:54 Richard Scales, <[email protected]> >>> wrote: >>> >>>> Many thanks Nick. >>>> Unless anything else comes to light I think I will forge ahead on that >>>> basis. I want to drive 15 segment panaplex displays (16 including the DP) >>>> so plan to use HV5530 or similar driver for the segments, probably two of >>>> them. Then the same MPSA42/MPSA92 driver arrangement for the HV though >>>> there are going to be 5 of those - I might be running low on pins it using >>>> a Wemos - I might consider a port expander for the extra pins needed - I >>>> need to check pins required - I think 4 for the HV register chain, 6 for >>>> the Anode switching (two drivers driving a 12 digit device - perhaps 5 for >>>> a 10 digit device) plus I want to read a PIR and talk to a BMP-280 sensor. >>>> Certainly a Wemos + port expander would do it - might get away with a Node >>>> MCU or similar. >>>> OK, I just realised that I can use a single 32 bit driver with two >>>> sets of 16 bits, one going to each bank of displays. >>>> It still has the same pin requirements of the processor I think. That >>>> will be a juggling excersise! >>>> - Richard >>>> >>>> >>>> On Wednesday, 1 November 2023 at 11:10:02 UTC Nick Sargeant wrote: >>>> >>>>> Hi, >>>>> >>>>> It’s not difficult. My fumbling attempts at a Nixie clock some time >>>>> ago used a 4:1 multiplex ratio, using four digits and only one decoder. I >>>>> used the same MPSA42/MPSA92 driver as your example. My multiplex function >>>>> was called at 100Hz, so each digit was refreshing at 25Hz. It doesn’t >>>>> flicker, and (whoa!) it is working 15 years later. >>>>> >>>>> The only mod I had was when switching between digits, I turned the >>>>> cathode drive off for a period of 20 microseconds, before selecting the >>>>> correct anode and turning on the next digit. This helped prevent >>>>> ghosting. >>>>> >>>>> >>>>> >>>>> On Wednesday, 1 November 2023 at 10:14:25 UTC Richard Scales wrote: >>>>> >>>>>> Actually - I just looked through an example over at: >>>>>> https://www.hackster.io/doug-domke/multiplexed-nixie-tube-clock-759ff5 >>>>>> >>>>>> ... and it all seems fairly understandable, have I overthought this? >>>>>> >>>>>> - Richard >>>>>> >>>>>> >>>>>> On Wednesday, 1 November 2023 at 09:22:03 UTC Richard Scales wrote: >>>>>> >>>>>>> The time has come when I need to get a handle the dark and >>>>>>> mysterious art of multiplexing. >>>>>>> I have an understanding of what needs to happen though am mostly at >>>>>>> a loss of how to implement it. >>>>>>> I am broadly assuming that I should be using some kind of interrupt >>>>>>> routine to make the actual display work whilst the rest of the code >>>>>>> gets on >>>>>>> with the job of working out what to display and when to display it. >>>>>>> Is it even going to be feasible to have some kind of interrupt >>>>>>> routine that decides what digits to light - set all the bits and then >>>>>>> sets >>>>>>> the right anode(s) on and then off again giving enough time for the >>>>>>> persistence of vision to produce a non flickering display when using >>>>>>> something like a wemos D1? >>>>>>> >>>>>>> I am thinking that the interrupt routine needs to increment which >>>>>>> digit(s) is/are being illuminated - set up the right bit pattern for >>>>>>> the >>>>>>> cathodes and turn on the relevant anode(s) - wait a little and then >>>>>>> turn >>>>>>> them off again. >>>>>>> My worry is that the amount of time that the displays should be left >>>>>>> on might be a little too long for the ISR as my understanding is that >>>>>>> these >>>>>>> should be kept as lean as possible. >>>>>>> >>>>>>> Do I even need multiple interrupts (my covid addled brain is >>>>>>> struggling to type let alone contemplate multiple ISR's!)? >>>>>>> Can the rest of my code run in a non time critical manner as it >>>>>>> works out what it wants to display where whilst the interrupt routine >>>>>>> merryly illuminates digits based on values which I store in a buffer >>>>>>> somewhere? >>>>>>> ... or does the rest of my code have to work in come kind of >>>>>>> state-machine fashion? >>>>>>> I would expect (hope) to handle display brightness via PWM signals >>>>>>> to HV Drivers. >>>>>>> I have no need for cross fade effects either - just basic >>>>>>> multiplexing of say 10 different multi segment displays. I am more than >>>>>>> happy to break up the displays into say 2 (or more) groups in order to >>>>>>> makes things a little easier. >>>>>>> >>>>>>> Can anyone point me in the right direction - ideally with some code >>>>>>> snippets that I can use as a foundation? >>>>>>> >>>>>>> Just to confirm, it is only the general implementation to drive the >>>>>>> displays that eludes me - the rest of the clock code is well defined >>>>>>> and >>>>>>> working well in a direct drive capacity. >>>>>>> >>>>>>> The desire to move to multiplexed operation is born out the the >>>>>>> desire to drive a greater number of displays with a greater number of >>>>>>> segments which could be done via direct drive but I foresee that >>>>>>> multiplexing the displays will simplify the electronics required. >>>>>>> >>>>>>> So many questions I know. I would be grateful for any pointers, >>>>>>> thank you. >>>>>>> >>>>>>> - Richard >>>>>>> >>>>>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "neonixie-l" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> To view this discussion on the web, visit >>>> https://groups.google.com/d/msgid/neonixie-l/e576bff1-8d65-4d53-b0cc-2ba5ba574232n%40googlegroups.com >>>> >>>> <https://groups.google.com/d/msgid/neonixie-l/e576bff1-8d65-4d53-b0cc-2ba5ba574232n%40googlegroups.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/279b0132-3f5a-488b-96e6-e9afca9c5902n%40googlegroups.com.
