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Monday, 3. March 2008
Blinkenlights Video
rsbohn
09:10h
... Link
Readerboard LED Display
rsbohn
08:40h
Found this on google: a 12x7 display driven by the ATTiny2313. They use the 74HC595 serial to parellel chip for the column drivers, and use transistors for the row drivers. Readerboard by CPU Ready Consulting My current firmware for my 5x7 board lights one LED at a time. I'm wondering if I could light a whole row at a time instead. My current limiting resistors are on each column, so it works better driving a row instead of a column. I used 330 ohm resistors, giving 15 milliamps per column with one LED on, that makes 75 milliamps out the row driver if all the LEDs are on. Too much to leave it on, bur perhaps the duty cycle is low enough I can get away with it... Anyway I'm hoping to post a video of the blinkenlights firmware running sometime soon. ... Link Wednesday, 27. February 2008
7x5 found a bad LED
rsbohn
11:53h
I added the last three LEDs to my 7x5 display awhile back, but didn't actually test them until this morning. One of them wasn't lighting up. Took a close look and I can see what a poor solder job I did. The flying wire wasn't even touching the next on in the row. Have to fix that next time I get the iron out. I want to try out the bidirection LED thing using this board. I want to read all seven LEDs in the rightmost column and see which one you are touching. For starters I'll just light up the whole row, so you can see a moving bar of lights when you run it. Eventually you could use this to set a value: the center line is no change, each row higher means increase faster, each row lower means decrease faster. Or, from top to bottom: +++ ++ + 0 - -- ---. To get started I created a new project in Atmel Studio for the Tiny2313 chip. This time around I'm not using the overflow interrupt for timer0, I'm just polling the overflow flag and resetting it. It didn't take long to get a row-strobe test pattern running. I've added sockets for ISP to the board, so I can just build the software and then upload it without disconnecting anything or removing the chip from the board. Sure makes things easier. I should save off a copy of the current firmware, it's nice to have a test pattern to make sure all the LEDs are lighting up. That's how I found the bad solder joint this morning. Find this story interesting? Check out uC Hobby! ... Link ... Next page
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8144 days of detection
mod: 12/3/08, 5:42 AM days of detection... PMOG owner
BiographyRandall Bohn lives in Orem, Utah, USA. He works as a Software Quality Engineer. He is a big fan of the AVR line of microcontrollers. He has been in the computer industry since 1989. Randall is married and has three children. rsbohn can be reached via gmail.com. status
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Arduino Starter Kit
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