Serial LED Display

[D396]

My display is behaving weird again. When I power it up it is slightly dimmed and does not display the right characters if anything at all. I think I might have switched the baud rate but I don't know what I switched it too and how to switch it back. This is a brand new display so I know it's not fried. Has anyone else used this display and if so have you had this happen and what did you do to fix it.

--Thanks

LINKS:
data sheet: http://www.sparkfun.com/datasheets/Components/LED/SFE-0012-DS-7segmentSerial-v3.pdf
Old post: http://www.picaxeforum.co.uk/showthread.php?t=13293
product page: http://www.sparkfun.com/commerce/product_info.php?products_id=9230

 

[lanternfish]

Hi

From the datasheet, to reset the baud rate to 9600 send (0x79)(0x02)

As for the dimmed start up state, have youe checked the supply voltage to the display?

Cheers

 

[D396]

I have tried to set the baud rate back to 9600 but I don't no at what baud rate to send the command. the voltage is 4.5V.

Is there a way to invert the usb cable so that I can control the display from the terminal?
something like the opposite of this discussion? http://www.picaxeforum.co.uk/showthread.php?t=13589&highlight=USB

 

[Andrew Cowan]

Yes, there is a way.

Connect the two grounds (cable 0V and display 0v).
The part of the cable that connects to the 'serial in' pin of the PICAXE will output the data at RS232 levels (-12v to +12v swing)(if using a standard serial port). This needs converting to TTL (0v to 5v swing).

HOWEVER - the AXE027 USB cable does not use RS232 levels - it uses pure TTL levels. Therefore, you can make a straight connection if using the AXE027 cable.

The USB010 adaptor cable uses RS232 levels, so this needs an adaptor.

A

 

[D396]

The serout command on a picaxe Is T9600 not n9600 so would I have to invert it using an inverter or FTDI_PROG? or would it just work as is?

 

[Andrew Cowan]

One of the two.

I'd personally use an inverter made from two resistors and pretty much any NPN transistor. See the Dr Acula's last post (post 27) in the thread about converting RS232 to TTL.

A

 

[D396]

I tried both methods an inverter chip and a FTDI_PROG nether worked.
when i send the characters 42 it displays 8L

 

[Andrew Cowan]

That doesn't sound like an inversion issue. Have you tried all the possible baud rates?

A

 

[D396]

Yes i have tried everything on the terminal

I think the display is dimmed because one of the data packets probably got messed up and sent the dimm command instead

 

[D396]

I am about to hook up a 28x1 set at 16mhz to try all possible baud rates .

 

[D396]

I got it the command I used was serout 7,T9600_16 , (0x04 , 0x03 , 0x02 , 0x05). Thank you for all the help!