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Finaly it's Done! - SkarkFun Graphics LCD Serial + Backpack Display


Woohoo, i can now control the display via 28x2, or via direct interface with visual basic applications which i create :D



Here is a link to the display i have: Serial Display with backpack

What i am trying to do is print: 1234567890 abcdefg

across the display, but i am running into a few problems, or maybe just one...

I know the display uses a baud rate of 115200bps

but i cannot seem to send information correctly even with the display connected directly to the serial port, it just sprays out gobbledegook symbals and numbers,

Here is what i get: [Display is connected directly to my terminal thru serial port]


////////////////////////////////////////////////////////////////////////////////////////////////////WHILE USING LOGICATOR/PROGRAMING EDITOR

hsersetup B9600_8, %111

hserout 0,(0x7C,0x07,0x22) //Set the display to baud rate 9600?
pause 2000
hserout 0,(0x7C,"1234567890 abcdefg") // Print text/numbers on the screen
pause 2000
goto main

Same thing happens....


As you can see this is just a simple, change baud rate and print some textr on the screen, but it'll just spray out random symbols and numbers.


The displays setup variables regarding baud rates.

Change Baud Rate:
Sending “<control>g (0x07)” followed by an ASCII
character from “1” to “6” changes the baud rate. The
default baud rate is 115,200bps,

but the backpack can be set to a variety of communication speeds:
“1” = 4800bps
“2” = 9600bps
“3” = 19,200bps
“4” = 38,400bps
“5” = 57,600bps
“6” = 115,200bps

As an example, to set the baud rate to 19,200bps,
send 0x7C 0x07 0x33, or from a keyboard send “|”,
<control>g and “3”. The baud rate setting is retained
during power cycling, so if it powers down at
19,200bps, it will next power up with that setting.


I have tryed using a terminal directly attached to the display using baud rate 115200bps and i type hello world and still gibberish comes out on the screen.

The display is brand new btw.

Please help asmuch as you can but please do not direct me to the manual above, i have allready studied it, tho you can have a look thru it and note down what i have missed.

Thanks TN.

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Have you tried putting the display in Command mode from the keyboard?

Like <Alt>+124 to put it in Command mode and then try the demo code with a <Control>d. Looks like by default the baud rate is 115,200. Maybe your program is not changing the baud rate.


Figures, it was not the command mode, it was the inverted signal from the AXE 027 Serial cable from what i was told at Sparkfun# IRC

What i had to do was use a transistor to flip flop the voltage, now everything is hunky dory! thanks to a guy named david_c

Here is what he sent me...

I hope this helps any others out there getting a display!


So if I'm running this LCD directly from a Picaxe (28x1), do I need transistor circuit to flip/flop the voltage?

Flip the "voltage" might not be right here... You are inverting the serial signal. A 1 becomes a 0 a 0 becomes a 1... I am not really sure why a transistor is needed here, the picaxes will output a true or inverted signal just not through the RX and TX pins. All the other "regular" serial pins as well as the hser pins will send a true or inverted signal.

HAHAA!! Thanks! :) I think I just found out that hserout can send out data at a much faster baud than serout. I probably have no clue what I am doing but now I can send  "1234567890 abcdefg" to the display thanks to you guys! Will have to play some more after school!