Code that worked with WINDSTAR LCD doesn't work with Newhaven LCD?

[jellis00]

I am totally embarrassed to tell everyone I found the problem....and it was one of my own making. I had an intermittent trace on the PCB between the MCU pin and the LCD's R/W pin. I wouldn't have found this if Darrel Taylor hadn't sent me a manual initialization routine that (as he said) if the LCD didn't work with it, it never would. When it didn't work it forced me to go back aqnd re-verify the PCB interfaces to the LCD. I had done this before but somehow missed the bad R/W interconnect....I suppose it was intermittenly working at the time.

At any rate, I totally appreciate all the good advice I received on this thread. The people that support this forum are the best.

As a small token of "give back" I am posting my final code for the routine that now works with the NEWHAVEN displays. I highly recommend them...they are low cost ($8.25 ea) and even though they don't require a backlight their reflectance performance gives a very readable display in even low light conditions....plus their tech support is outstanding.
Here is code for initializing their 2x8 LCD modules...they have one for 5vdc operation and one for 3vdc operation that has exactly the same physical and electrical interfaces...and both at $8.25.

InitializeDisplay: ' Subroutine to initialize NEWHAVEN NHD-0208AZ-RN-YBW
'================= ' 2x8 LCD2X8 LCD display

' Blink LED_GRN twice to indicate entered IntializeDisplay
For i = 0 to 1
HIGH LED_GRN
Pause 500
LOW LED_GRN
PAUSE 500
Next

' LCD DEFINES FOR USING 2x8 LCD with PortA
DEFINE LCD_DREG PORTA ' Use PORTA for LCD Data
DEFINE LCD_DBIT 0 ' Use lower(4) 4 bits of PORTA
' PORTA.0 thru PORTA.3 connect to
' LCD DB4 thru LCD DB-7 respectively
DEFINE LCD_RSREG PORTA ' PORTA for RegisterSelect (RS) bit
DEFINE LCD_RSBIT 4 ' PORTA.4 pin for LCD's RS line
DEFINE LCD_RWREG PORTC ' LCD read/write port
DEFINE LCD_RWBIT 2 ' LCD read/write bit
DEFINE LCD_EREG PORTA ' PORTA for Enable (E) bit
DEFINE LCD_EBIT 5 ' PORTA.5 pin for LCD's E line
DEFINE LCD_BITS 4 ' Using 4-bit bus
DEFINE LCD_LINES 2 ' Using 2 line Display
DEFINE LCD_COMMANDUS 10000' Command Delay (uS)
DEFINE LCD_DATAUS 100 ' Data Delay (uS)

' DEFINE LCD Control Constants
Line1 CON 128 ' Point to beginning of line 1 ($80)
Line2 CON 192 ' Point to beginning of line 2 ($C0)

' Test the LCD during initialization
LCDOut $fe,1:FLAGS=0:Pause 250 ' Clear Display
LCDOut $fe,Line1,"LCD TEST" ' Display on 1st line
Pause 500
LCDOut $fe,Line2,"Power On!" ' Display on 2nd line
PAUSE 1000
Return

[jmgelba]

Bumping this old thread as I'm about to use a Newhaven display for the first time. I have a NHD-0216K1Z-NSRGB-FBW 16x2 5.0V display. http://www.newhavendisplay.com/specs...-NSRGB-FBW.pdf I'll be using a 18F2550 for the first time. The LCD will be on portB and in 4 bit mode.

Looking at the above working code, is that really a 10000us delay? What does the FLAGS=0 mean?

[jellis00]

Looking at the above working code, is that really a 10000us delay?

Yes, it was, but this code was a very early version of my attempts to make it work. I just looked up in my latest code and I am now using the following statements that work with the display I am using, the NHD-0208AZ-RN-YBW:
DEFINE LCD_COMMANDUS 1500 ' Command Delay (uS)
DEFINE LCD_DATAUS 44 ' Data Delay (uS)
You may have to play with these values for your particular display module. Also don't be afraid to call Newhaven tech support...they are outstanding and helped me a great deal.

What does the FLAGS=0 mean?

Go to the page in the PicBasic Pro Compiler manual (it is also online if you can't find your manual) and look up the page that describes the use of the command LCDOUT. It explains what FLAGS=0 is used for. It is used to reset an internal flag to tell the program to initialize it the next time it uses LCDOUT after having been powered down and then powered back up. Very important if you are shutting off power to the LCD during the program when it is not being used to save battery power. That is why I used it.

I hope all of this helps.

BTW, one of the ongoing problems many people have had who use the NEWHAVEN LCD display modules is how to get a clean looking mounting, which normally requires a bezel. Bezels are hard to come by for these displays. I found a company that has a good set, one which worked with mine. Go to http://www.rmfproducts.com to see what they offer. Prices are also reasonable....their Model 140-1 for my LCD display size only costs $2.15 each in quantities of 1-99, and $2.00 each for 100 or more.

I hope all this helps you.
/s/ John Ellis

[jmgelba]

Thank you for that wealth of information.

This display will be mounted in a custom cast aluminum enclosure with a graphical overlay over the top. This will also contain the push buttons, the bezel info is good to know. The project is a control and monitor for a 400W LED driver.

Which PIC did you end up using?

[jellis00]

Which PIC did you end up using?

Because most of my applications have a USB interface, I have favored using either the 18F2550 or 18F4550. If you don't need a USB interface these are probably over kill, but they are so low in price and have so many IO pins, they are a good choice even if you don't need the USB. I use the 18F2550 whenever I can because it is a 20 pin IC and a lot smaller than the 4550 for board layout. I published an article in the recent Forum Competition that you can see by going to that location on the Home page. Mine is the Ultrasonic Ranger application and all of my code is posted there, including the routines that intialize and use the NEWHAVEN display.

[jmgelba]

Nice. I'm also using a 18F2550 - for the first time. I've started browsing through the datasheet and am currently finishing up the schematic and about to start on the layout.

This project calls for several analog in's, the LCD, the USB, 4 switch inputs, and control of a digital pot. Oh and a couple of indicator LED's.

Nothing like jumping in with both feet!

[jellis00]

So it soounds like you are still building schematic/layout and haven't started coding yet??
When you get into the coding of the USB interface you will probably run into problems. I did, and got a lot of help from Darrell Taylor and the Forum. When you get to that stage and need help, let me know and I may be able to refer you to some well hidden postings that will help you with the USB.