Sphere478 wrote on 2022-12-24, 03:22:

Do they have to be tied to ground through a resistor? Or is straight to ground okay?

I assume straight to ground is fine. They would be read the same as if a switch was installed on the pin and pressed.

serisman wrote on 2022-12-24, 03:40:

Sphere478 wrote on 2022-12-24, 03:22:

Do they have to be tied to ground through a resistor? Or is straight to ground okay?

I assume straight to ground is fine. They would be read the same as if a switch was installed on the pin and pressed.

On many ICs a switch would go through a resistor for such a binary on/off signal for protection. (Jumpers like fsb or bf jumpers, etc on motherboards)

But I think you are are probably right. But consult datasheet. Perhaps the example circuit section might show

Sphere478 wrote on 2022-12-24, 04:24:

serisman wrote on 2022-12-24, 03:40:

Sphere478 wrote on 2022-12-24, 03:22:

Do they have to be tied to ground through a resistor? Or is straight to ground okay?

I assume straight to ground is fine. They would be read the same as if a switch was installed on the pin and pressed.

On many ICs a switch would go through a resistor for such a binary on/off signal for protection. (Jumpers like fsb or bf jumpers, etc on motherboards)

But I think you are are probably right. But consult datasheet. Perhaps the example circuit section might show

It would be a pretty rare IC that required a protection resistor for an INPUT pin. When configured as INPUT, you can almost directly connect the pin directly to GND or VCC. Sometimes an external pull-up or pull-down resistor is warranted, but most ICs nowadays (and especially 8051 based) have pull-ups built in, and those aren't about protection to begin with. Now, if you wanted to protect against accidentally configuring the pin as OUTPUT and writing a high to it, then yes a resistor might be warranted (depending on whether we are talking about Open-Drain (8051 default) or Push-Pull. I don't think we need one in this case, though, since on power-up the port defaults to INPUT mode. Also the existing switch on P4.6 isn't using one, and P4.7 hasn't been used as an OUTPUT on any other hardware variations.

👍🙂

Sphere478 wrote on 2022-12-24, 03:22:

Do they have to be tied to ground through a resistor? Or is straight to ground okay?

Sorry been away over xmas.

Straight to ground is fine.

Serial support is nearly finished, just gotta iron out some final stuff.

this turns out to be an exciting project! kudos!
IMHO a small serial->usb adapter will also be a great idea, much like the ones for the amiga:

keropi wrote on 2022-12-28, 07:26:

this turns out to be an exciting project! kudos! IMHO a small serial->usb adapter will also be a great idea, much like the ones […]
Show full quote

this turns out to be an exciting project! kudos!
IMHO a small serial->usb adapter will also be a great idea, much like the ones for the amiga:

ye the amiga adapters are nice, really wanted something like that

Stupid question, whats the diffrent btw CH559L and CH559T? does any of them work or does it need to be CH559L?

*never mind saw the size now 😉

i want to order some MAX3232, but is there any specific model? there are a few of them on https://www.lcsc.com/ and i have no clue which one that it should be, there is like MAX3232ID MAX3232CD MAX3232CDR and so on 😉 would be grateful if someone could point me to the right one 😉

tabm0de wrote on 2022-12-28, 18:21:

i want to order some MAX3232, but is there any specific model? there are a few of them on https://www.lcsc.com/ and i have no clue which one that it should be, there is like MAX3232ID MAX3232CD MAX3232CDR and so on 😉 would be grateful if someone could point me to the right one 😉

The MAX3232C** is the 'commercial' version with temperature range from 0 to 70. The MAX3232I** is the 'industrial' version with temperature range from -40 to 85. Either will work just fine in this application.

The MAX3232*D* is the SOIC-16 'D' package type with 3.9mm wide body. The other package types ('DB', 'DW', 'PW') won't fit on the board's footprint.

So, the compatible part numbers are:
* MAX3232CDR / MAX3232CDRG4
* MAX3232IDR / MAX3232IDRG4

Note: The MAX3232*** is a newer version of the older MAX232, which should also work (potentially with different capacitor values).

Edit: Looks like TI also has the MAX3232E which would also be compatible. Specifically: MAX3232ECDR & MAX3232EIDR

Other manufactures have similar ICs / part numbers that would also be compatible, but you would need to check the datasheet for compatibility.

serisman wrote on 2022-12-28, 19:22:

The MAX3232C** is the 'commercial' version with temperature range from 0 to 70. The MAX3232I** is the 'industrial' version with […]
Show full quote

tabm0de wrote on 2022-12-28, 18:21:

i want to order some MAX3232, but is there any specific model? there are a few of them on https://www.lcsc.com/ and i have no clue which one that it should be, there is like MAX3232ID MAX3232CD MAX3232CDR and so on 😉 would be grateful if someone could point me to the right one 😉

The MAX3232C** is the 'commercial' version with temperature range from 0 to 70. The MAX3232I** is the 'industrial' version with temperature range from -40 to 85. Either will work just fine in this application.

The MAX3232*D* is the SOIC-16 'D' package type with 3.9mm wide body. The other package types ('DB', 'DW', 'PW') won't fit on the board's footprint.

So, the compatible part numbers are:
* MAX3232CDR / MAX3232CDRG4
* MAX3232IDR / MAX3232IDRG4

Note: The MAX3232*** is a newer version of the older MAX232, which should also work (potentially with different capacitor values).

Edit: Looks like TI also has the MAX3232E which would also be compatible. Specifically: MAX3232ECDR & MAX3232EIDR

Other manufactures have similar ICs / part numbers that would also be compatible, but you would need to check the datasheet for compatibility.

Thanks really appreciate the information, I know how too solder that about it 😉

serisman wrote on 2022-12-28, 19:22:

The MAX3232C** is the 'commercial' version with temperature range from 0 to 70. The MAX3232I** is the 'industrial' version with […]
Show full quote

tabm0de wrote on 2022-12-28, 18:21:

i want to order some MAX3232, but is there any specific model? there are a few of them on https://www.lcsc.com/ and i have no clue which one that it should be, there is like MAX3232ID MAX3232CD MAX3232CDR and so on 😉 would be grateful if someone could point me to the right one 😉

The MAX3232C** is the 'commercial' version with temperature range from 0 to 70. The MAX3232I** is the 'industrial' version with temperature range from -40 to 85. Either will work just fine in this application.

The MAX3232*D* is the SOIC-16 'D' package type with 3.9mm wide body. The other package types ('DB', 'DW', 'PW') won't fit on the board's footprint.

So, the compatible part numbers are:
* MAX3232CDR / MAX3232CDRG4
* MAX3232IDR / MAX3232IDRG4

Note: The MAX3232*** is a newer version of the older MAX232, which should also work (potentially with different capacitor values).

Edit: Looks like TI also has the MAX3232E which would also be compatible. Specifically: MAX3232ECDR & MAX3232EIDR

Other manufactures have similar ICs / part numbers that would also be compatible, but you would need to check the datasheet for compatibility.

Sorry serisman, i tried to dm, i have the boards and just wanted to do the order now for the parts, but sadly im not sure about the "RN3 is 1k (or whatever works with choosen RGB LED)" as it is not a part of the BOM, would it possible to give me some light regarding what part it is 😉

tabm0de wrote on 2023-01-02, 12:56:

Sorry serisman, i tried to dm, i have the boards and just wanted to do the order now for the parts, but sadly im not sure about the "RN3 is 1k (or whatever works with choosen RGB LED)" as it is not a part of the BOM, would it possible to give me some light regarding what part it is 😉

Sorry. Apparently my account isn't old enough to trust with DM privileges. I can see your DM, but can't respond to it.

Anyway, the RN3 is just a resistor network. i.e. 4x 1k resistors in a single package to make it easier to solder. The 1k value isn't all that important. I wouldn't go much lower, but you can go a bit higher to dim the RGB LED more. I think the exact ones I used are LCSC #C153136, but pretty much any 0603 (x4) of the right resistance range should work.

serisman wrote on 2023-01-02, 18:34:

tabm0de wrote on 2023-01-02, 12:56:

Sorry serisman, i tried to dm, i have the boards and just wanted to do the order now for the parts, but sadly im not sure about the "RN3 is 1k (or whatever works with choosen RGB LED)" as it is not a part of the BOM, would it possible to give me some light regarding what part it is 😉

Sorry. Apparently my account isn't old enough to trust with DM privileges. I can see your DM, but can't respond to it.

Anyway, the RN3 is just a resistor network. i.e. 4x 1k resistors in a single package to make it easier to solder. The 1k value isn't all that important. I wouldn't go much lower, but you can go a bit higher to dim the RGB LED more. I think the exact ones I used are LCSC #C153136, but pretty much any 0603 (x4) of the right resistance range should work.

Thanks! 😀

tabm0de wrote on 2023-01-02, 20:35:

serisman wrote on 2023-01-02, 18:34:

tabm0de wrote on 2023-01-02, 12:56:

Sorry serisman, i tried to dm, i have the boards and just wanted to do the order now for the parts, but sadly im not sure about the "RN3 is 1k (or whatever works with choosen RGB LED)" as it is not a part of the BOM, would it possible to give me some light regarding what part it is 😉

Sorry. Apparently my account isn't old enough to trust with DM privileges. I can see your DM, but can't respond to it.

Anyway, the RN3 is just a resistor network. i.e. 4x 1k resistors in a single package to make it easier to solder. The 1k value isn't all that important. I wouldn't go much lower, but you can go a bit higher to dim the RGB LED more. I think the exact ones I used are LCSC #C153136, but pretty much any 0603 (x4) of the right resistance range should work.

Thanks! 😀

Yep, no problem. Curious to see how your build goes. If you keep some notes on your findings, I can update the GitHub with better BOM/instructions if needed.

@rasteri do you have a model number for the enclosure that you are using for the serial version (AXP)?

florian3 wrote on 2023-01-07, 17:45:

@rasteri do you have a model number for the enclosure that you are using for the serial version (AXP)?

Sure, it's the "E-case A" from Lincoln Binns, 40mm length. https://lincolnbinns.com/shop/aluminium-enclo … case-a-kit.html

The exact same case is available from other companies under other part numbers though, so you might be able to get it cheaper from a supplier near you if you're not in the UK

Any new firmware updates...? 😬

rasteri wrote on 2023-01-07, 17:55:

Sure, it's the "E-case A" from Lincoln Binns, 40mm length. https://lincolnbinns.com/shop/aluminium-enclo … case-a-kit.html

The exact same case is available from other companies under other part numbers though, so you might be able to get it cheaper from a supplier near you if you're not in the UK

Thanks!

I built a board yesterday, works fine so far. I haven't been able to test the serial port yet because the footprint didn't match the dsub 9 connectors that I already had.

florian3 wrote on 2023-01-07, 18:39:

I built a board yesterday, works fine so far. I haven't been able to test the serial port yet because the footprint didn't match the dsub 9 connectors that I already had.

Yeah the DB9 footprint I used from the kicad library is a little odd. The only footprint I didn't make myself. Sigh.

I'm sure there must be connectors somewhere that fit it.