flashjazzcat Posted January 9, 2014 Share Posted January 9, 2014 Doing a refit of one of my SIO2SD units (Retr0Brite, new LCD, etc), and I fancy adding activity lights on the SIO2PC component: I did this on a unit I made for AA member Philsan, but that one had an AtariMax SIO2PC in it, with ready-made hook-ups for the LEDs. This one is the standard home-made MAX232/RS232 version. What I have in mind is two additional LEDs on the front: one for transmit, one for receive. Any ideas how best to wire these up to the back of the DB9? Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted January 9, 2014 Share Posted January 9, 2014 I think if you tied a 470 ohm resistor on the outputs of the Max-232 that connected to LED's would be fine. I did a similar mod to my 410 back in '83 and it worked just fine... Quote Link to comment Share on other sites More sharing options...
flashjazzcat Posted January 9, 2014 Author Share Posted January 9, 2014 I think if you tied a 470 ohm resistor on the outputs of the Max-232 that connected to LED's would be fine. I did a similar mod to my 410 back in '83 and it worked just fine... Right - so (bearing in mind I'm a total dunce when it comes to circuits) I just hook the LED's anode to the relevant pin of the MAX232 via a 470Ohm resistor, and the cathode leg to GND? Thanks! Quote Link to comment Share on other sites More sharing options...
AtariGeezer Posted January 9, 2014 Share Posted January 9, 2014 (edited) An example: Edited January 9, 2014 by AtariGeezer 3 Quote Link to comment Share on other sites More sharing options...
flashjazzcat Posted January 9, 2014 Author Share Posted January 9, 2014 Very nice indeed! Thanks for your help Jay. Quote Link to comment Share on other sites More sharing options...
HiassofT Posted January 9, 2014 Share Posted January 9, 2014 FYI: TxD and RxD are at a logic '1' level if idle, so you might want to connect the LED between +5V and RxD/TxD. Otherwise the LEDs are on by default and switched off if some data is transmitted. Also be sure to use high efficiency LEDs and use a series resistor of some 4k-10k (depending on the LED's specs) so you don't load the RxD/TxD lines too much. so long, Hias 2 Quote Link to comment Share on other sites More sharing options...
flashjazzcat Posted January 14, 2014 Author Share Posted January 14, 2014 FYI: TxD and RxD are at a logic '1' level if idle, so you might want to connect the LED between +5V and RxD/TxD. Otherwise the LEDs are on by default and switched off if some data is transmitted. Also be sure to use high efficiency LEDs and use a series resistor of some 4k-10k (depending on the LED's specs) so you don't load the RxD/TxD lines too much. Thanks Hias - sure enough, this works well. Quote Link to comment Share on other sites More sharing options...
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