dmd notes - freetronics forum

8/20/2019 DMD Notes - Freetronics Forum

http://slidepdf.com/reader/full/dmd-notes-freetronics-forum 1/4

Freetronics ForumFreetronics: Arduino-compatible open source electronics

Skip to content

Search… Search Advanced search

DMD Notes

Post ReplyPrint view

Search this topic… Search Advanced search

6 posts • Page 1 of1

DMD Notes (#p11804)Quote (./posting.php?mode=quote&f=26&p=11804)

(javascript:void(0);)Postby Brissieboy » Sat Jan 18, 2014 7:02 am

I made some notes while I was playing with the DMD and thought they might also be of some

value to others, so I tidied it up a little. I hope it is OK. Corrections, comments, additionswelcome.

UPDATE:

Corrected the information in the attached file on screen RAM index calculation by adding info

for multi‐dimensional DMD arrays.

Attachments

DMD Notes.txt (./download/file.php?id=341)

(13.31 KiB) Downloaded 236 times

Last edited by Brissieboy (./memberlist.php?mode=viewprofile&u=13102) on Mon Jan

26, 2015 3:23 am, edited 1 time in total.

Top

Re: DMD Notes (#p11811)Quote (./posting.php?mode=quote&f=26&p=11811)

(javascript:void(0);)Postby stryker » Sat Jan 18, 2014 11:08 am

Nice work. I especially read with interest your note about the OE line not having an explicit

start state. I of ten wonder why these DMDs fire up with random lit LEDs on them and there's

the simple explanation right there. I might hack our present controller board to provide that

pull‐down resistor ‐ and will remember that for any future revisions.

Any chance you're keen on documenting how the fonts work? I've had a tilt at making some

custom typefaces (2 DMDs tall, and a full 16px high type without vertical spacing) but have so

far avoided revisiting it with equal parts procrastination, and getting distracted.

Cheers !

Geoff

Top

Re: DMD Notes (#p11816)Quote (./posting.php?mode=quote&f=26&p=11816)

8/20/2019 DMD Notes - Freetronics Forum

http://slidepdf.com/reader/full/dmd-notes-freetronics-forum 2/4

(javascript:void(0);)Postby Brissieboy » Sun Jan 19, 2014 1:06 am

stryker,

You need to be a little careful here with a 16 pixel high font. If you want to have the

descenders (as used on lower case g, j, p, q, y) you need to have a couple of pixels available

below the bottom line of the other 'normal' characters. That effectively reduces the font

size. Of course you could define the characters so that they did not have descenders but they

don't look as nice.

I have made my own 16 pixel font that uses ALL the available height of the DMD, but I did not

need lower case in this font. I only defined the characters from space (0x32) to underscore

(0x5F). This was to get the largest display possible for my primary display which only needed

a very limited number of characters on‐screen at a time ‐ when I need to do other things I

change fonts.

As I worked out how it all goes together, I added some details in comments to the font file

which may be helpful and I have attached a copy here. I used a very crude excel spreadsheet

to do the translation from visual display to data to minimise errors in this part of the process.

Attachments

MyBigFont.h (./download/file.php?id=283)(14.02 KiB) Downloaded 410 times

Top

Re: DMD Notes (#p11820)Quote (./posting.php?mode=quote&f=26&p=11820)

(javascript:void(0);)Postby stryker » Sun Jan 19, 2014 5:38 am

Thanks for sharing this. For my purpose I only need a handful of upper case alphas and 0

through 9 so expect this will be perfect. Thanx! Geoff

Top

Re: DMD Notes (#p12050)Quote (./posting.php?mode=quote&f=26&p=12050)

(javascript:void(0);)Postby stryker » Thu Feb 13, 2014 10:29 am

Hi,

Small update after the real world got in the way of this project ‐ it does look great. Thanks

for the annotations in that file too.

Cheers ! Geoff

Top

Re: DMD Notes (#p13807)Quote (./posting.php?mode=quote&f=26&p=13807)

(javascript:void(0);)Postby Brissieboy » Mon Jan 26, 2015 3:26 am

Updated the DMD notes attachment in the original post to show correct calculation of screenRAM index for multi‐dimensional DMD arrays. Original was only true for 1 DMD high.

Top

Display posts from previous: All posts Sort by Post time Ascending Go

8/20/2019 DMD Notes - Freetronics Forum

http://slidepdf.com/reader/full/dmd-notes-freetronics-forum 3/4

Post Reply

Print view

6 posts • Page 1 of1Return to “Dot Matrix Display”

Jump to

Arduino-Compatible Boards

ArduPhone

CNCPlotter

Eleven EtherDue

EtherMega

EtherTen

Goldilocks

KitTen

LeoStick

LeoStick examples, software and fun sketches

Pebble v2

StepDuino

USBDroidArduino Expansion Shields

BTSH: Bluetooth Shield

DLOCK: RFID Door Lock Shield

ES: Ethernet Shield

HBRIDGE: H-Bridge Motor Driver Shield

LCDK: LCD & Keypad Shield

RX315/RX433: 315MHz and 433MHz Receiver Shields

SECSENSE: Security Sensor Shield

SH-RFIDLOCK: RFID Lock Shield

TS: Terminal Shield

Modules, Sensors, & Displays

Module Support

Dot Matrix Display

Experimenters Kit

4x4x4 RGB Cube

OLED128 Display

Raspberry Pi

Raspberry Pi Expansion Boards

ArduSat Arduino Satellite

General ArduSat Discussion

ArduSat Payload Processor ModuleGeneral Discussion

Random Chit-Chat

Project Showcase

Product / Device Ideas

Practical Arduino

Arduino Workshop

3D Printing

SuperHouseTV Home Automation

Arduino Shield List

Shield Discussion Shield List Site Discussion

Who is onlineUsers browsing this forum: No registered users and 1 guest

8/20/2019 DMD Notes - Freetronics Forum

http://slidepdf.com/reader/full/dmd-notes-freetronics-forum 4/4

Powered by phpBB® Forum Software © phpBB Limited