Repurpose 1200xl LEDs

[Frankie]

Is there a way to rewire one of the 1200 XL LEDs to show SIO activity?

The side cart I use has an led but when it's plugged in you can even see it on a 1200.

 

Frank

[ACML]

Don't see why not. They are 5VDC LEDs. I once had an 800XL with 256K RAM and added an LED to show read/write status to the RAM drive.

Edited August 7, 2016 by ACML

[ACML]

Don't see why not. They are 5VDC LEDs. I once had an 800XL with 256K RAM and added an LED to show read/write status to the RAM drive.

Edited August 7, 2016 by ACML

[+mytek]

Is there a way to rewire one of the 1200 XL LEDs to show SIO activity?

The side cart I use has an led but when it's plugged in you can even see it on a 1200.

 

Frank

 

Looking at this schematic, it seems like it would be a fairly simple matter to intercept the LED signal at connector J7. Since all of the LED's have a common ground, you would just need to provide an in-line 330 ohm resistor to feed it from a 5vdc source. Now as to how to show SIO activity on an LED, that is something still to be figured out, but I would image using a transistor switch tied into the SIO data line might be a way to go to be sure there are no loading problems (instead of trying to drive the LED directly from SIO).

 

 

- Michael

Edited August 7, 2016 by mytekcontrols

[Rybags]

A thought I had is do a custom OS to do the job. LED on when Command goes active. Off when SIOV returns.

Wouldn't work for custom serial routines though.

[Bryan]

A single logic chip could monitor the 2 data lines and produce a composite of them. Then, with a short off-delay you could have an LED that stayed on during all SIO.

[Timothy Kline]

The way I picture it is using a similar method to that of an LED indicator on a digital logic probe to let you know that the line is open or closed for traffic. Integrating that into the SIO is beyond my current level of experience, for sure; although I've had the same consideration with a 1200XL here, too.

 

--Tim

[flashjazzcat]

Interesting, but nothing you wire to the command line of the SIO connector will cause an LED to flash during data transfer on a parallel device like the OP's SIDE cart. The LED on the SIDE cart reflects activity on the IDE status register, so to do this on the Atari SIDE you'd need to be hooked into the address bus and watch for reads and writes on $D5F0.

[+mytek]

Interesting, but nothing you wire to the command line of the SIO connector will cause an LED to flash during data transfer on a parallel device like the OP's SIDE cart. The LED on the SIDE cart reflects activity on the IDE status register, so to do this on the Atari SIDE you'd need to be hooked into the address bus and watch for reads and writes on $D5F0.

 

Opps I totally missed that point

 

Yep if you want to see activity on SIDE2 in the simplest way possible, you'd have to tie into the on board HD LED, which is something I'll be doing on my new 1088XEGS system. Of course that means you couldn't easily disconnect the cartridge from the system. So the harder way would be to do as FJC suggested and decode the address bus for activity at $D5F0.

 

- Michael

[BillC]

 

Looking at this schematic, it seems like it would be a fairly simple matter to intercept the LED signal at connector J7. Since all of the LED's have a common ground, you would just need to provide an in-line 330 ohm resistor to feed it from a 5vdc source. Now as to how to show SIO activity on an LED, that is something still to be figured out, but I would image using a transistor switch tied into the SIO data line might be a way to go to be sure there are no loading problems (instead of trying to drive the LED directly from SIO).

 

 

- Michael

Q9/Q10 are transistors already controlling the L1/L2 LEDs, isolating them from PB2/PB3 and connecting new signals wouldn't be difficult.

The following is from sheet 6 of the Sobola 1200XL schematics:

Edited August 7, 2016 by BillC

[AtariGeezer]

Should be easily modifiable to use tri-state LED's to add two more status signal displays...