Hello

I was just wondering if anyone has an idea for the best way to drive 4x large 7 segment displays that are common anode (which is not the norm) that each require 12V forward voltage to run.

The displays in question are here:
http://www.sparkfun.com/commerce/product_info.php?products_id=8530

Datasheet:
http://www.sparkfun.com/datasheets/Components/YSD-1600AR6F-89.pdf

It has been mentioned on here before, however there were no shared outputs between the displays which I am requiring due to the PCB footprint this driver board will be going on to.

Basically I want the arduino to either output I2C, SPI or digitial outputs to a chip which can then drive 4 of these displays. Basically a shift register or multiplexor, but to drive common anode.

I want 12 wires coming out. The 7 segments and the decimal point, which would be common wires between all 4 displays, and then 4 select outputs to chose the display to update.

I have looked at the 74HC595 shift register and thought about putting a darlington array after it or something - but is this the best way?

The displays take 12V (from 11.6v to 12.4v), so with a supply of 12v going through the darlington arrays, you get a voltage drop which would dim the displays (as I have tested). I could use FET's I suppose, but is there another solution?

Thanks

Hey
That is the same display as I have by the looks of it. $1US a piece is damn cheap, but has a minimum order of 100 units.

They are a serial backpack enabled LCD, so you just connect it direct to your arduino to send data to it via the TX pin, but it does need a -9V power source which you can get from a MAX232 chip easily.

Nice find though. The site suggests it has a white backlight though, which I know mine does not have. Unless its slightly different I can only assume that is not correct, but I am about to email them to find more info.

Another thing though, this LCD most likely is a RAW LCD out of the original AT&T terminals, and I doubt it would have the modified EEPROM installed into the back of the unit in order to send it stuff from PC's or Arduino etc. I have another post about this.

Thanks for the link though
James

PM'ed you Ran - Thanks

Hello

Yeah exactly what I am finding. I have a few graphic LCD's, however physically their size is too small for what I am wanting for a project. The old character displays would have been perfect.

I may just have to use the 24x8 character display I have - it will be fine.



Cheers

Hello

Im in the search for a large character LCD (large number of characters that is). I have seen a few around in the past on old computers and equipment, however I cannot seem to find any available these days.

I have found this particular product which uses a 40x8 LCD.
http://resource.boschsecurity.com/documents/FN-LCD-N-R_DataSheet_enUS_T5719113227.pdf

I do not know any details about it however.

There are a few listed here, althought I cant find any of these available anymore.
http://mdfs.net/Info/Comp/LCD/

Does anyone know of any current models which are in the 40x8 size?

I currently have a few 24x8 LCD's, however I am looking for more characters still. One with a serial backpack would be a perfect solution, however not essential.

Any help anyone can give would be magic.

Thanks

Looking at the 2313 datasheet, I could have actually used that as it has INT0 and INT1, plus 2 other ports for PCINT's, seperate XTAL pins, I2C and a UART.

Ah well.

Hi guys, thanks for the replies.

I am familar with AVR Dude, and have used Bascom-AVR and Pony-prog etc prior to moving to Arduino IDE.

By proper I meant for an offical type method from the Arduino IDE, rather than skipping to another program in order to achieve the desired result.

What I am trying to do is build a Arduino programmed modular system which I can use on a number of projects, both private and commercial which I can just use 1 programming package for, rather than writing the main code in Arduino and then having to go to something else to program or write the code.

I have a old Parallel ICSP programmer aswell as a newer Sparkfun USB programmer which I use to program the bootloaders.

I have now redesigned the board I had the 85 on, to use a standard 168 instead, as there isnt much in the cost and a few more pins dont matter - just the ease of use with Arduino IDE appealed, and using the same cable. Petty I know.

Thanks for the replies
James

Forget that, a quick search found a discussion for the attiny85 which is in the same boat.
Maybe I will use a slightly larger, but still small atmega instead of the 85, one with a UART - im not pressed for size and making the upload progress easier until a 'proper' method of uploading using IDE is found - I think I will just wait.

Another question on this... how do you program these chips with arduino IDE if there is no serial port for a FTDI header? I know you can put the bootloader in via the ICSP header, but can you program the chip with Arduino IDE through this too, or do you have to use another program?

Thanks

Actually, looking further - Port B only has the two XTAL pins, the Reset pin, and the INT0 pin... so thats not much use.

hmm.

Ah I see - I knew there had to be some sort of sacrifice.

So with these Tiny's, there are only 2 ports, bugger.

I see the pin that INT0 uses is also PCINT10... how does that work?
From what I can tell, INT0 has the highest priority, but why would you use PCINT10 if you could use INT0?

PCINT10 in on Port B, and INT0 is therefore on Port B too... But I assume INT0 will have its own vector?
So in saying that, can I have 3 interrupts which use seperate vectors? INT0, a PCINT from Port A and a PCINT from Port B?

Is that correct, or assuming incorrectly.

Ta

Datasheet here:
http://www.atmel.com/dyn/resources/prod_documents/8006S.pdf

Hello

I am just building an an IO board for a project, which will have its own processor on board, and I have decided to use the AtTiny84.

I am just wanting to check a few things as I havent used a AtTiny before where so many things are shared on pins.

One of these is how to hook up the header for programming in the bootloader, just to make sure I have it right  .

Very noob type question, but just want to make sure - pretty sure this is right, but I have been fooled before.

The 6 or 10 pin ISCP header, are these correct?:
MOSI goes to PA6 (which does state MOSI in the description)
MISO goes to PA5 (which states MISO in the desc)
SCK goes to PA4? (it states USCK, assume this is correct?)
RESET goes to PB3 (assuming as RESET is in the desc)

The datasheet refers to these ports as part of the 'USI 3 wire mode' - which I havent heard of referenced as that before, but I assume this is what the bootloader is programmed over.

For I2C comms, are these correct?:
I2C-SCL goes to PA4?
I2C-SDA goes to PA6?

The datasheet refers to these as part of the 'USI 2 wire mode' which I assume is the TWI/I2C?

From reading on here, there is a bootloader already written to suit the '84, I can only assume it works as desired and people are using it no problems...

This particular board will be communicating to a main board which will have a ATMega1284P on it, via I2C comms.
The board is going to be used solely for counting pulses, basically a high speed counter board. I need to utilise either 2 of 4 external interrupts. I notice this chips has INT0 and then has Pin Change interrupts... another assumption is that these pin change interrupts function in a similar way to the normal external interrupts say on a standard Arduino board?
I need to do more reading, but if someone knows straight off if these can be used just like a normal interrupt, where they can trigger an ISR etc, then that would be great to tell me.

Thanks in advance

James

Not Arduino, but very related - in 2003 I purchased a kit off this guy.
http://www.frankvh.com/mp3-player.html
He designed this all and sold a few kits and I still have it working at home. It was before MP3 player were as widespread as they are now. Uses a computer HDD has a LCD etc and even has USB to load songs on to the HDD. Was very flash at the time and alot of my friends were very envious

What you want to do is similar, but with newer technology, touch screen etc and with the Arduino. This project could be ported to the Arduino as it uses a Atmel Mega, but not really relevant.

Just thought you may be interested to have a read of what he did, as I am assuming you would want to build all this into a custom PCB once done, rather than having an arduino with shields stacked on it as your final product.

Some of the stuff he used you cant get anymore, however their will be newer things which do the same if not more these days.

Thought you may be interested

Cheers
James

SPI and I2C (and HardwareSerial) are completely separated and independent.

Indeed - Im not sure where I said something to negate this... I am not using HardwareSerial for any backbone comms...

I was eluding to using SPI hardware pins MISO, MOSI, SCK for the backbone, but then using seperate general IO pins at the same time to implement a software version of SPI at the same time, to have a seperate comms network basically... whether or not this is possible I dont know.

If I go down the I2C backbone path then I wont need the software SPI implementation anyway, and it looks like I will go down the I2C backbone path from what you have said.

The 3 address pins (some devices have only two or one!) are only part of the address. There is an additional fixed 4 bit part specific for the chip. So you can have 8 different chips of the same kind at one bus. Many chips are produced with two different addresses (the second version called ....A, this is not a better chip, but just one with an alternative address in it) Processors can of cause choose their own address out of 127.

Ahh - very good. I was not aware of this. That is very good news.

Thank you