Sending commands via 'C' printf

Jason van Ryan · Post by **Jason van Ryan** » Fri Jun 19, 2009 11:29 pm

Hello. I am trying to set up an LK204-24 for 1200 baud (I'd prefer 300, but 1200 is the lowest)

I can print to the display e.g. 'hello Jason' with no problems at 19200 (display default) - so all this side of things are working

I'm sending the change baud rate command via a printf statement from a uController but it does not seem to work.

printf("%X%X%X",0xFE,0x39,0x53)

Can anyone point me in th e right direction here?

Thanks

Jason

Post by **Ray** » Sat Jun 20, 2009 2:20 am

try %c instead of %x also you might want to experiment with the backlight commands to get your printf working since it has an visible observable result unlike the change baudrate command.

Jason van Ryan · Post by **Jason van Ryan** » Sat Jun 20, 2009 9:32 pm

Thanks - I'll give that a try.

Jason van Ryan · Post by **Jason van Ryan** » Sun Jun 21, 2009 2:59 am

Hi I tried a few things. I selected to turn the blinking block cursor on (I've got one of the PLED displays)

printf("%x",0xFE53); - still no luck

this as well

printf(0xFE53); - still no luck

Post by **Ray** » Sun Jun 21, 2009 10:23 am

printf("%c%c",0xfe,0x53);

Jason van Ryan · Post by **Jason van Ryan** » Sun Jun 21, 2009 9:29 pm

Hi Ray,

I tried that as well, but no luck.

I'm wondering if it s because I have to 'unlock' before I can make any changes?

Jason van Ryan · Post by **Jason van Ryan** » Sun Jun 21, 2009 9:29 pm

Hi Ray,

I tried that as well, but no luck.

I'm wondering if it s because I have to 'unlock' before I can make any changes?

Jason van Ryan · Post by **Jason van Ryan** » Sun Jun 21, 2009 9:30 pm

Hi Ray,

I tried that as well, but no luck.

I'm wondering if it s because I have to 'unlock' before I can make any changes?

Jason van Ryan · Post by **Jason van Ryan** » Sun Jun 21, 2009 9:36 pm

One other question. I dont see any detials in the manual about the RS232 spec -i.e. is it 8 bits, 1 stop, parity/no parity etc.

although I am printing ok 99% of th e timer to the dispay, I am getting some odd characters (graphic symbol) every now and then.

Raquel · Post by **Raquel** » Mon Jun 22, 2009 10:17 am

Hello Jason,

The RS232 port settings are: 8 data bits, 1 stop bit, no parity, no flow control and 19200 default baud, which you should be able to change to 1200 with the command 0xFE 0x39 <baud>.

Now depending on the board you have, <baud> could be 0x53 or 0xFF.
You mentioned you have an LK204-24 and later mentioned PLED. Maybe you have a PK202-24-USB or a PK202-25?

Thanks,

Jason van Ryan · Post by **Jason van Ryan** » Tue Jun 23, 2009 7:02 am

The marking on the PCB has the PK-204-25 REV 2 place on the model table marked with a little dot. Its a red display type.

Raquel · Post by **Raquel** » Tue Jun 23, 2009 8:42 am

Hi Jason,

Sorry but the part number you mentioned does not seem to be right (specially when you mentioned that the display is red). Is it possible for you to please take a picture of the display module's front (powered on) and back?

Anywho, have you tried 0xFF or 0x53 as parameter for the command 0xFE 0x39?

edit:
After sending the command, wait for about 100 ms delay and start communicating in 1200 baud. The change is effective (almost) immediately.

Thanks,

Jason van Ryan · Post by **Jason van Ryan** » Thu Jun 25, 2009 6:26 am

Hello Raquel,

I've solved the problem and can now send commands to the display.

Here is what I used to change the baud rate to 1200

printf("%C%C%C",0xFE,0x39,0x53); /* change baud rate to 1200 */

Jason