New Ninox mouse "Ninox Astrum" - with swapable shells - Page 235 - Overclock.net - An Overclocking Community

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New Ninox mouse "Ninox Astrum" - with swapable shells

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post #2341 of 2410 (permalink) Old 09-22-2019, 06:17 PM
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bst, on your 3360 pcb, what are the chips on the bottom left?
if they're for spi level conversion, fyi that isn't necessary at all.

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post #2342 of 2410 (permalink) Old 09-23-2019, 03:59 AM
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Quote: Originally Posted by qsxcv View Post
bst, on your 3360 pcb, what are the chips on the bottom left?
if they're for spi level conversion, fyi that isn't necessary at all.

Thanks, I just checked the datasheet and you're right, theres no max voltage for the SPI listed. I guess the tindie 3360 was just being extra careful?

On MISO it converts the voltage to 5V going to the MCU, looks like that isn't needed either.
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post #2343 of 2410 (permalink) Old 09-23-2019, 04:30 AM
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the tindie board was built to handle 3.3v and 5v. I'm not sure that would be possible using resistors. you could get away with even few level converters by changing the design to 3.3v mcu but that could make side buttons more susceptible to double click.
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post #2344 of 2410 (permalink) Old 09-23-2019, 05:17 AM
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Quote: Originally Posted by gipetto View Post
the tindie board was built to handle 3.3v and 5v. I'm not sure that would be possible using resistors. you could get away with even few level converters by changing the design to 3.3v mcu but that could make side buttons more susceptible to double click.
The 3.3v/5v to 1.9v is handled by the voltage regulator chip, then the level converters use the 1.9v from that to change the SPI voltage to 1.9v.

I think I might have figured out why they are needed now.

Basically VDDIO on the sensor is set to 1.9v from the voltage regulator, and so the SPI voltage should match the VDDIO, so the level converters are used to set the SPI signals from the MCU to 1.9v, to match the VDDIO voltage.

The VDDIO has a maximum voltage of 3.6v, so it can't be set to 5v, and the only other option is 1.9v, unless another voltage regulator is used, so might as well use the same 1.9v.

So I am assuming that VDDIO's voltage is meant to match the SPI voltage (I guess so it can interpret the signals properly?), if that's the case then you can't use 5v SPI signals, so I'd have to keep the level converters.
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post #2345 of 2410 (permalink) Old 09-23-2019, 05:32 AM
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I find all the technical talk hard to understand. I learned about level shifting from this article. There's no harm I think in sticking to the proven design and avoiding bugs down the line. I understand that most of the cost increase comes from adding another part reel, since the level shifters are all the same part there's little difference in overall cost between 5v mcu + level shifters and 3.3v mcu with voltage divider shifting and extra 3.3v regulator like in the hackaday article.(assuming that it works reliably for long periods)

https://hackaday.com/2016/12/05/taki...evel-shifters/

edit: You should probably use the v5 3360 srom also it has less smoothing than the v3 and v4.

https://github.com/zaunkoenig-firmwa...om_3360_0x05.h

Last edited by gipetto; 09-23-2019 at 07:06 AM.
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post #2346 of 2410 (permalink) Old 09-23-2019, 07:22 AM
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Yeah I could use resistors for the level shifting, but I think the level converters are better. How much better, idk But they aren't that expensive so why not.

It says in the sensor datasheet that the max voltage for the VDDIO pin on the sensor (which is the reference voltage for the SPI signals), is 3.6v. If it was 5 or 6v, then the SPI signals and VDDIO power could just come straight from the MCU. Or if I was using a 3.3v MCU then the 3.6v max wouldn't be a problem.

There is probably no good reason why 5v won't work, because for the actual signal its ok, it'll be below and above the thresholds necessary. But because its saying 3.6v max for the VDDIO pin, it makes me think that 5v would damage it somehow. Maybe not immediately, but over time. Maybe I'm wrong about that and it'll be fine, but I wouldn't want to take the risk without being 100% sure.
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post #2347 of 2410 (permalink) Old 09-23-2019, 08:04 AM
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I forgot to say, the factory is going ahead with the 0.8mm PCB.

The weight of the mouse should be just under 80g, and if you remove the magnets and use smaller mouse feet, which will be included in the box, then it'll have its weight reduced another 2.5g, so it'll weigh about 76-77g.
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post #2348 of 2410 (permalink) Old 09-23-2019, 09:05 AM
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my personal preference for doing things is 3.3v everywhere (mcu and vddio on 3360).

i don't think 3.3v vs 5v is enough to impact the switches significantly.

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post #2349 of 2410 (permalink) Old 09-24-2019, 05:42 PM
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Quote: Originally Posted by qsxcv View Post
my personal preference for doing things is 3.3v everywhere (mcu and vddio on 3360).

i don't think 3.3v vs 5v is enough to impact the switches significantly.
Its a nice clean way to do it, idk if I would change to 3.3v though, I don't see any big problems with the transceivers (they're not expensive), and I want to run the MCU at full speed, just because I'm paranoid it might be needed at some point
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post #2350 of 2410 (permalink) Old 09-24-2019, 06:40 PM
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yea i wouldn't change it at this point

did you adjust the timers in the firmware so that they know about 16MHz though?

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