MAX7219 32x8 LED Dot Matrix Display

[Noor_Fatimah_I_H]

MAX7219 32x8 LED Dot Matrix Display.fzpz (19.8 KB)

[vanepp]

Not a bad part, but it has an error. The pcb svg has ellipses instead of circles and thus the holes are not drilled in the gerber output. The gerber drill.txt file

; NON-PLATED HOLES START AT T1
; THROUGH (PLATED) HOLES START AT T100
M48
INCH
%
T00
M30

is empty meaning no holes. I knew to look for this by running your part through FritzingCheckPart.py (which can be found in this tutorial on parts making)

Part creation howto part 1 breadboard and pcb

Someone in this forum post requested help to fix up a part. So while doing that I decided to record what I needed to do in order to fix the part to provide a tutorial to create new / fix broken parts. If you start from the Tarjeta S4A EDU.fzpz file posted in the above thread, you should be able to recreate my improved part posted in the same thread. I started by loading the original part in to Fritzing, that indicates breadboard is (at first look anyway) pretty good, but schematic and pcb are…

which produces this output (edited for size!)

$ FritzingCheckPartw.py ‘part.MAX7219 32x8 LED Dot Matrix Display_c7830f5cafd7c607a76591ec76457968_5.fzp’

**** Starting to process file Startup, no file yet

**** Starting to process file part.MAX7219 32x8 LED Dot Matrix Display_c7830f5cafd7c607a76591ec76457968_5.fzp

**** Starting to process file svg.breadboard.MAX7219 32x8 LED Dot Matrix Display_c7830f5cafd7c607a76591ec76457968_5_breadboard.svg.bak

**** Starting to process file svg.schematic.MAX7219 32x8 LED Dot Matrix Display_c7830f5cafd7c607a76591ec76457968_5_schematic.svg.bak

**** Starting to process file svg.pcb.MAX7219 32x8 LED Dot Matrix Display_c7830f5cafd7c607a76591ec76457968_5_pcb.svg.bak

File
‘part.MAX7219 32x8 LED Dot Matrix Display_c7830f5cafd7c607a76591ec76457968_5.fzp.bak’

This is a through hole part as both copper0 and copper1 views are present.
If you wanted a smd part remove the copper0 definition from line 47

…

Error 65: File
‘svg.pcb.MAX7219 32x8 LED Dot Matrix Display_c7830f5cafd7c607a76591ec76457968_5_pcb.svg.bak’
At line 104

Connector connector0pin is an ellipse not a circle, (gerber generation will break.)

Error 74: File
‘svg.pcb.MAX7219 32x8 LED Dot Matrix Display_c7830f5cafd7c607a76591ec76457968_5_pcb.svg.bak’
At line 104

Connector connector0pin has no radius no hole will be generated

Error 65: File
‘svg.pcb.MAX7219 32x8 LED Dot Matrix Display_c7830f5cafd7c607a76591ec76457968_5_pcb.svg.bak’
At line 105

Connector connector1pin is an ellipse not a circle, (gerber generation will break.)

Error 74: File
‘svg.pcb.MAX7219 32x8 LED Dot Matrix Display_c7830f5cafd7c607a76591ec76457968_5_pcb.svg.bak’
At line 105

…

which corresponds to this in the svg (here displayed in Inkscape, which looks to be what you are using):

Here we see there is an rx and ry (and the element is labeled ellipse not circle!) rather than a r

to fix this copy rx to ry like this

That still hasn’t fixed it, just enabled the fix. To change it to a circle from an ellipse you need to move the pad one position left then right with the tool bar like this

The pad ends up in the same place it started but has been converted from an ellipse to a circle in the process. Unfortunately you need to then do this one at a time for all the rest of the pads, I don’t know of a way to do this as a group (if anyone does please post it!) which is a large pain, but at least this works if with a lot of work. That will then generate the holes in the gerber output. Hope this helps!

Peter

[Noor_Fatimah_I_H]

MAX7219 32x8 LED Dot Matrix Display.fzpz (20.0 KB)

Thank you for your thoughtful insights, Peter! I’m resubmitting the updated version after making the suggested changes:-

1. Replaced all ellipses with proper circles in the PCB Drawing.svg

2. Used Inkscape to manually convert each pad by nudging them left and right, just as you described. It was a bit tedious, but totally worth it..

3. I also tested the updated SVGs using FritzingCheckPart.py to confirm the fixes.

[Noor_Fatimah_I_H]

While designing the Fritzing part for the MAX7219 32×8 LED Dot Matrix Display, I wondered if I could incorporate live simulation.

Inspired by this idea, I have written a blog post, "Explore Electronic Design Simulators with Arduino MAX7219 Heart Match Game," published on my blog, Wiztaqnia.

Read the full post here: Explore Electronic Design Simulators with Arduino MAX7219 Heart Match Game - Wiztaqnia ®

Would love to hear your thoughts! Thanks again for helping me grow through this process.

[vanepp]

I know only enough about simulation to be dangerous, @fai who developed the simulator can give you a better answer, but Fritzing currently has no capability to do CPU simulation, and while it has been requested, I expect it is too large a change to be practical. Even if we could do CPU simulation that would likely not apply to parts as they (other than the spice data) have no data to allow simulation and I expect it would be difficult to add.

Peter

[fai]

Yes, this would require arduino simulation and simulation of the spi interface. And in addition, a spice model for this part, which I do not know if it exists. Currently, it is not feasible in fritzing.