Designing my own TB6560 AHQ driver boards...

One minor nit: its better to use 3.3V instead of 5V for the OPTO LED anode side
because some parallel port outputs only swing to 3.3V. This will leave the
OPTOs LEDs partially on when they should be off if their anodes are returned to 5V.

The data pins are push-pull and when powered by 3.3V only swing to 3.3V.
(some control outputs are open drain with a pullup but change to push-pull in EPP/ECP modes)

If you 'pull' 3.3V outputs up through the OPTO LED to 5V, you will have current
flowing in the OPTO when it should be off

Parallel port _inputs_ must be compatible with 5V signals, but parallel port outputs only guarantee TTL compatibility (0.8V maximum low level output, 2.4V minimum high level output at maximum loads)

Thanks PCW,

Perhaps the best thing here is to get my PC up and running, force the outputs and measure what happens...

Any more guidance on the interface of Parallel ports is welcomed, as this is my first venture into the unknown!

Dell haven't yet supplied any information on their Parallel Port configuration (Dell Dimension 1100 PC).

Cheers, Scott.

PCW wrote:

some control outputs are open drain with a pullup but change to push-pull in EPP/ECP modes

Can these modes be set in EMC2? Or is a BIOS / motherboard setting?

Cheers, Scott

I've just found that SPP and ECP can be set by System Setup (end of sheet 22 in the attached PDF)

Cheers, Scott.

ScottBouch wrote:

I've just found that SPP and ECP can be set by System Setup (end of sheet 22 in the attached PDF)

Cheers, Scott.

On many Dell and other motherboards, EPP mode can be ENABLED, but the BIOS
setting does not actually set the port to that mode. You do this by writing
0x80 to the I/O port 0x402 higher than the data register, at least for the
standard port at 0x378. We do this in many of the LinuxCNC drivers
for devices that use EPP mode.

Thanks for all the support on Parallel ports! I have one thought, i did read in one of the manuals to save blowing up your motherboard port, using inexpensive PCI card ports is acceptable.

I know a lot of people are usine MESA boards, but they are not cheap. A quick look on ebay revealed some PCI parallel boards for less than £5.. Would one (or two to increase I/O) of these cause me a nightmare? Is it better to spend a little more?

Cheers, Scott.

Awesome, Cheers!