Seetron Serial LCD troubles...

KamPutty · 2008-07-14 19:55

Hi all,

Okay, I'm finally back to this serial lcd hookup project...

I've got a Seetron bpp-420vy serial LCD 4x20

+5, -, and serial (rs232 or inverted TTL)

I have the serial connected to P5 and am using "simple serial"

I just get garbage on the screen...

Hee is the code

CON

  _clkmode = xtal1 + pll16x                             ' use crystal x 16
  _xinfreq = 5_000_000                                  ' 5 MHz cyrstal (sys clock = 80 MHz)

  ' setup serial pins
  outputPin = 5
  inputPin  = -1
  baud      = 9600

  ' debug pins
  LEDPinGood = 16
  LEDPinBad  = 23 
        
OBJ

  serial : "simple_serial"                              ' bit-bang serial driver

PUB main

  ' turn off LED's
  dira[noparse][[/noparse]LEDPinGood]~~
  dira[noparse][[/noparse]LEDPinBad]~~
    
  if serial.init(inputPin, outputPin, baud)
    !outa[noparse][[/noparse]LEDPinGood]                                   ' turn on good led
    serial.tx(12)                                       ' clear screen                      
    serial.tx(6)                                        ' blinking cursor
    serial.tx("K")
    serial.tx("a")
    serial.tx("m")        
  else
    !outa[noparse][[/noparse]LEDPinBad]                                    ' turn on bad led                    

  repeat

Any thoughts why I'm getting garbage? I tried this on 2 different, but same, LCD's and they both do the same thing (garbage)

~Kam (^8*

Mike Green · 2008-07-14 20:13

From the Simple_Serial comments:

'' To specify inverted baud (start bit = 1), use a negative baud value:
''
'' serial.start(0, 1, -9600)
''

KamPutty · 2008-07-14 23:05

Mike, et. al.,

Ooops, sorry, I forgot to mention I did try the negative baud also...it's just not writing "kam" on the screen...I get garbage, or "ka" etc...maybe a timing thing or something...I'll have to put my analizer on it...

But, the code it sound and hook up, ya?

I continue....

~Kam (^8*

Matthew Hay · 2008-07-15 01:41

Well the first thing that I notice is that you don't have any delay before trying to use the LCD. The examples on seetron's site show a 1 Sec delay to allow the LCD to stabilize. I also noticed that the lcd has a couple of switches for settings on the back, one being for baud rate 2400/9600 and the other being for mode selection normal/old, you might want to verify those match up appropriately too.

Shawn Lowe · 2008-07-15 03:23

Any problems Ive had with my seetron (2X16 and not using a propeller) had to due with timing problems (resonator with an SX)

Hope that helps

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Shawn Lowe

When all else fails.....procrastinate!

KamPutty · 2008-07-15 14:51

Hi shawn,

How did you adjust the timing? I did notice that if I put "stalls", I can get my name to appear at times...I've used these displays without any issues before on a pic...

Stupid Prop chip...working to fast...

~Kam (^8*

QuattroRS4 · 2008-07-15 18:34

Is this an old or new version .. Apparently there has to be a 1mS delay after clearing the screen in the older versions .. see attached jpg .. I have also attached the user pdf in case you didn't have it ..

also a good reference http://www.seetron.com/ser_an1.htm

Are the LCD and Properller circuit grounds common..Just a thought..

Regards,
John

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'Necessity is the mother of invention'

Post Edited (QuattroRS4) : 7/15/2008 6:51:31 PM GMT

Shawn Lowe · 2008-07-15 18:46

I had to use a resonator, which is precise enough for communications with the LCD. Are you sure you have the right baud setting?

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Shawn Lowe

When all else fails.....procrastinate!

Seetron Serial LCD troubles...

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