Second I2C address not responding

[LinkMTech]

Okay, try inserting brackets around your OUTP variable this way:

mainloop:
  FOR LP = 0 TO 9
    READ LP, OUTP
    I2CWRITE SDA, SCL, CHP001, [OUTP]	'WRITE 1's
    PAUSE 250
    I2CWRITE SDA, SCL, CHP010, [OUTP]	'WRITE 10's 
    PAUSE 250
    I2CWRITE SDA, SCL, CHP100, [OUTP]	'WRITE 100's 
    PAUSE 250
  NEXT LP	
Goto mainloop                           'LOGICAL END

I just tried removing the brackets on a short test program I've been playing with and it didn't work right anymore until I put them back.

[Amoque]

Wow... How dumb do I feel? It works perfectly now! I've been sitting here scratching a bald spot behind my right ear as I review every comma, wire, and word on the manual page - all the while looking right past the missing brackets.

Thanks, Louie. I guess I just don't know how to say it more plainly than that. I really appreciate the help.

I just did a little more extensive testing... moved the digits around and fiddled with the timing some... it is rock solid now, every digit works in every position - fast - without skipping or cogging. Very nice! Thank you ALL again for your attention, time, and effort.

[Art]

Congrats

I'm confused how the 1st I2C address is even responding.

I'm also still stuck on this, and thought I still must be misunderstanding something.
It shouldn't have worked at all as far as I can tell.

Pictures of display device?

[LinkMTech]

Cool! You're welcome Amoque, glad you can continue on your quest.

I'm with Art, still confused with the addresses that are working. It must be an early version not mentioned in the data sheet I was looking.

[Amoque]

Haha! A question I can answer for you! The part number is PCF8574A - the "A" differing only by its upper address nibble, 0111xxx. If I include the write bit (I do because no read is ever done from the completed modules), the address range is $70 - $7F. With both the '74 and '74A, I can put 16 modules on a bus and make my own "Wheel of Fortune"! Did I not say I bought quite a number of these?

A picture so that you can envy my good fortune...



The small item is a standard dot-matrix LED for comparison.

--All the best,
Amoque

[Art]

I was hoping they were matrix displays
They do look like a good way to make a project flexible.
I wouldn't want to be making the front panel for them though!