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Half way done and wish I had made a PCboard

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I took the info of using the TPIC6B595 and failed to realize that it in itself would not work.
My solutions are remove the sockets for the TPIC6B59's and replace with a 24pin? socket for the MAX7219.
Another though I had was install 32 pnp transistors connected to the TPIC6B595 shift registers and add more connections to the already jumbled mess of wires.
Perhaps the easiest solution is put some 74hc595 shift registers in place of the TPIC6B595 and leave the resistors and 2803 as is.
While not the best fix but the easiest one IMO so I could leave most if not all the present wiring in place except make a few changes on the shift register / pic connections.
As for using info from the 8 x 8 matrix project. I plan to use basically the same code but include the shift.bas.
 
I took the info of using the TPIC6B595 and failed to realize that it in itself would not work....

Um, excuse me, what? What you failed to realize was that the words on the data sheet matter. I said that a 74HC595 driving a ULN2803 could be replaced by a TPIC6B595. A ULN2803 can only sink current. A TPIC6B595 will fit the same place in the circuit.

But instead of following that suggestion, you copy&paste(tm) a schematic too blurry to read, replace the 74HC595 (with its standard TTL output) in that circuit with a TPIC6B595 without stopping to understand what " open drain" means in the data sheet.

This is especially idiotic since you've tried (and obviously failed) to use a ULN2803 (with its open collector output) to source current in one of your past fiascos.

And once again you've slapped the face of those trying to help you with a very heavily implied "I got bad information. It was his fault it didn't work."
 
I had viewed a website describing the usage of shift registers and it mentioned using the TPIC6B595 but tried accessing that website again and it is not working. YES I misinterpreted information. I didn't say I got bad information I just didn't utilize the information correctly and using the downed website as helpful information was wrong on my part.
Now how to correct my mess with as little reconfiguring as possible. I think using the 32 PNP transistors might be the answer but Have seen several working similar matrix circuits using the 74HC595 but current draw is a concern as the 74hc595 is rated at 20ma output but using the common cathode run the risk of exceeding that maybe?
 
...Have seen several working similar matrix circuits using the 74HC595 but current draw is a concern as the 74hc595 is rated at 20ma output but using the common cathode run the risk of exceeding that maybe?...

If you can even figure that out, you've learned nothing from dozens of posts on this topic.

I suggest you go back and read my posts in SEARCH feature is gone? Scrolling on an 8 x 8 matrix as I explained everything in good detail there.

Aside from that I guess you'll need to find another patsy.....er.....benefactor.... to help you out. The list is growing short for what reason I cannot imagine.
 
I plan to use the basic code I used for the 8 x 8 matrix I have that works but in this project (8 x 32) I decided to go with this example
Making a 8×40 LED matrix marquee using shift registers | Embedded Lab
Brad uses same as well as other similar circuits. Ordered 74hc595's from Jameco as they get stuff here in Salmon fast.
I reread most if not all the posts related to the 8 x 8 project. The big mistake I made was misinterpreting using the TPIC6B595 in place of the 74hc595.
 
I'm sure you'll make it work since you've learned so much. I truly look forward to seeing your result. I'm certain it will be astonishing.
 
You said you bought common cathode matrices. You have everything you need as I have explained several times.

Drive the rows (anodes) from a port on the PIC...each with a current limiting resistor.

Connect each column (the cathodes) to a TPIC6B595 output.

Rotate a "1" across the line of TPIC6B595s.

Questions? See my previous posts.

Done. As am I.

Goodbye.
 
Now that sounds easier than using the 74hc595's BUT I need 32 ports just for the anodes if I am interpreting right?
using a 18F4520 so I should have a few extra ports. Need to calculate.
 
Geez oh f&$king grief. I've explained it clearly as possible without doing it myself....again.

Not going to happen.
 
If I connect as per post 18 then 32 port pins for the anodes and 3 for the shift register then using a 18f4520 (dip-40 pkg) you run out of pins.
36 for anodes, 2 for Vdd and 2 for Vss. Data sheet says 35 I/O pins.
That is following post 18
 
Hi Mr Deb,

If you've mounted and wired your displays in a configuration of 8 common cathode rows and 32 common anode columns, Raj Bhatt's 74HC595 circuit on Embedded-Lab should work fine. I would make sure to drive the display one row at a time for a 1/8th (12.5%) duty cycle.

You could also replace the 8-bit serial-to-parallel sinking driver ICs with 8-bit serial-to-parallel source driver ICs. I only know of one, the **broken link removed**.

As an alternative, turn each display 90° on your board and wire them up as 8 common anode rows and 32 common cathode columns. Then you can keep the 8-bit serial-to-parallel TPIC6B595 sinking drivers for the columns but you'll need 8 PNP transistors or 8 P-Channel MOSFETs to "source" the anode rows. Again, I would recommend driving the display one row at a time for a 1/8th (12.5%) duty cycle instead of driving one column at a time (1/32nd duty cycle).

Good luck on your project.

Cheerful regards, Mike
 
Geez....read the words – they have meanings.

image.jpg
 
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Just buy as many of **broken link removed** as you need.

JonSea, don't like to say it but I did. :smug:

Mike.

I love the MAX7219 and use them to drive 7-segment displays. They are cheap on eBay. If you have to pay full price, look at the AS1106 – it is the same as the MAX7219 (in terms of pinout and operation) with a few additional commands for a much lower list price.

I also love using modules like the one you posted for one-off or small-scale projects. Often, the assembled board is cheaper than the parts cost alone.

Here's a project I did for the FAA using a MAX7219.

image.jpg
 
I wish I had known about the Max7219 that Pommie posted about. I am going to purchase some for future use. No time to wait for mail from China.
Thanks. While waiting for the 74hc595's from Jameco I am rewiring my board one pin at a time.
I now understand what Jon was referring to about driving the anodes off of port pins and cathodes to the shift registers. A picture is worth a 1000 words.
 
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