LCD BARgraphs

[Christopher4187]

I'm not smart enough to figure out why this is happening but the problem has been identified. Whenever the program sends "Threebars," it goes wacky. If I modify the code from this:

SELECT CASE BARtemp
            CASE IS > BARloop
                     LCDOUT ThreeBARS              ; send 3 bars    |||
            CASE IS < BARloop

to this:

SELECT CASE BARtemp
            CASE IS > BARloop
                
            CASE IS < BARloop

it will run fine. Of course only two bars will be displayed but something with the code is causing a problem in the display.

I made a bargraph routine and it works just fine so the problem is a conflict between the lcdbar inlcude file and the OLED screen. There isn't enough experience in my brain to figure out why so maybe someone else can. It was a good experience for me because I never used bargraphs before and I learned a lot from DT's program. The only thing I don't like about the program below is that it keeps writing over the previous graph, even if the data doesn't change, so if the bargraph stays at 100% or a high amount, you can see the bargraph flicker a little bit. I'm guessing that a routine is needed whereby nothing is written unless the number changes.

C0     VAR     BYTE
 C1     VAR     BYTE
 C2     VAR     BYTE
 C3     VAR     BYTE
 C4     VAR     BYTE
 C5     VAR     BYTE
 C6     VAR     BYTE
 C7     VAR     BYTE

C0  = $40
C1  = $48
C2  = $50
C3  = $58
C4  = $60
C5  = $68
C6  = $70
C7  = $78

lcdout 254,C0,REP 16\8
lcdout 254,C1,REP 24\8  
lcdout 254,C2,REP 28\8
lcdout 254,C3,REP 30\8
lcdout 254,C4,REP 31\8
BOX     VAR     WORD
LINE    VAR     WORD

FRICT_PAD_TQ_BAR    VAR    WORD
LINE_DISPLAY        VAR     BYTE
BOX_DISPLAY         VAR     BYTE
FRICT_PAD_TQ        VAR    WORD


MAIN: 
 
FRICT_PAD_TQ_BAR=(FRICT_PAD_TQ-12)/5
BOX_DISPLAY=127
LINE_DISPLAY=0
FOR LINE = 0 TO FRICT_PAD_TQ_BAR
    LCDOUT $FE, BOX_DISPLAY,LINE_DISPLAY
    LINE_DISPLAY=LINE_DISPLAY+1
        IF LINE_DISPLAY=5 THEN
            BOX_DISPLAY=BOX_DISPLAY+1
            LINE_DISPLAY=0
        ENDIF
    LCDOUT $FE,212, DEC FRICT_PAD_TQ_BAR
NEXT LINE
BOX_DISPLAY=0
LINE_DISPLAY=0
GOTO MAIN

[Dave]

Chris, Have you written code to look at the BUSY bit? I think you would be a bit supprised to find out just how long it takes some SPOOLED commands to execute. I have had this problem before with some NewHaven displays and with there lack of documentation you just have to figure out things on your own. What I would do is, write a routine to first set an output bit and connect a scope, then look at the busy bit after you send a command string to the display. re-check the busy bit to be clear, reset the output bit when the bit is clear and you would be supprised. Why do you think they make it available? You as the programmer are supposed to knowlegable enough to use the BUSY bit. Otherwise, don't complain about someone elses routines not working unless you know what the problem is....... Happy Thanksgiving......

[Christopher4187]

Otherwise, don't complain about someone elses routines not working unless you know what the problem is

It wasn't a complaint, Yoda. I said there was a conflict between DT's program and the OLED screen. That's a factual statement. In fact, I'm very appreciate of the information Darrel posts on here. Exhibit A:

Darrel, this program is awesome by the way!

I learned a lot from DT's program.

I've been using the OLED screens for over a year now. I know people have had problems with the displays but I really like them and never had a problem. If you know of a better OLED screen, by all means a better suggestion is always welcomed. Do you think people on here use Newhaven LCD/OLED screens? I'd be inclined to say yes. Given that fact, someone along the way is going to run into this same problem.

If there's a simple solution or a new line of code can be inserted to make it work correctly, why not do it? The main intent of the post was to elicit substantive discussion regarding the Newhaven OLED screen and DT's program. It doesn't work "off the shelf," which is perfectly fine. However, if Darrel or anyone else can provide a solution to make the program work, that would be great, but everyone on here understands there are no obligations. I don't have enough programming knowledge to contribute a lot here, so maybe this is a chance for me to do so if nobody else has the time to do it.

Personally, a lot of time has been spent on this and I'm really learning a lot. Even if I don't find a solution, it's time well spent.

[Dave]

Chris, Just use the busy bit to confirm the display is ready for the next command.... As I said in the my first return post, the commands are processed by the display far too slowly and I see no delays in your code after any of the cursor control commands and you are probably running it in 4 bit mode as opposed to 8 bit mode which now allows for even more data to be lost. looking at the timing constraints in the data sheet, I'm supprised the thing is working at all. The processor onboard the display is probably doing far more work than your code is. If you are commited to using this type of display with it's down falls because it looks good then you MUST you it as it was intended to be used it you expect it to relay the information correctly. No more to say...

[Christopher4187]

looking at the timing constraints in the data sheet, I'm supprised the thing is working at all. ....If you are commited to using this type of display with it's down falls because it looks good then you MUST you it as it was intended to be used it you expect it to relay the information correctly. No more to say...

Anyhow, for anyone who is using a Newhaven OLED display and wants to use Darrel's bargraph routine, you only have to modify a few things, which only takes about 30 seconds to do so. Here is what you need to do:

Make this portion of the code:

    LCDOut $FE,$40,REP $15\8                  ; Custom char 0 - 3 lines  |||
    LCDOut $FE,$48,REP $14\8                  ; Custom char 1 - 2 lines  ||
    LCDOut $FE,$50,REP $10\8                  ; Custom char 2 - 1 line   |

To make it look like this:

    LCDOut $FE,$48,REP $15\8                  ; Custom char 0 - 3 lines  |||
    LCDOut $FE,$50,REP $14\8                  ; Custom char 1 - 2 lines  ||
    LCDOut $FE,$58,REP $10\8                  ; Custom char 2 - 1 line   |

You have change the numbers in the other two character sets if you use blocks and boxes.

You also have to modify this code:

ThreeBARS CON 0                                ; Identify the Custom Characters
TwoBARS   CON 1
OneBAR    CON 2

To this:

ThreeBARS CON 1                                ; Identify the Custom Characters
TwoBARS   CON 2
OneBAR    CON 3

By modifying the lines of code above, the bargraph will display correctly on your OLED screen. I tested the bargraph a few different ways and it worked 100% of the time. I hope this is able to help someone.

[SteveB]

THE CHANGES IN THE ABOVE POST ARE INCOMPLETE!!!

If you make those modifications, you need to change all of the custom character declarations. Otherwise, the other styles will not work properly. Here are the other modifications (shown with the first set for context):

; --- lines Style custom chars ----
CharsetLines:
    LCDOut $FE,$48,REP $15\8                  ; Custom char 0 - 3 lines  |||
    LCDOut $FE,$50,REP $14\8                  ; Custom char 1 - 2 lines  ||
    LCDOut $FE,$58,REP $10\8                  ; Custom char 2 - 1 line   |
RETURN

; --- boxed Style custom chars ----
CharsetBoxed:
    LCDOut $FE,$48,$1F,REP $15\6,$1F          ; III
    LCDOut $FE,$50,$1C,REP $14\6,$1C          ; II
    LCDOut $FE,$58,REP $10\8                  ; I
RETURN

; --- blocks Style custom chars ----
CharsetBlocks:
    LCDOut $FE,$48,REP $1F\8
    LCDOut $FE,$50,REP $1C\8
    LCDOut $FE,$58,REP $10\8
RETURN

[Darrel Taylor]

So, what you're saying is that if you use Custom Character 0 on those displays, everything goes crazy?
Displaying the wrong characters on the wrong lines.

And by just not using Cust. Char 0, everythings AOK?
On both of your dispays?

That's a new one ... but it sounds typical for Newhaven.

[Christopher4187]

THE CHANGES IN THE ABOVE POST ARE INCOMPLETE!!!

If you make those modifications, you need to change all of the custom character declarations. Otherwise, the other styles will not work properly. Here are the other modifications (shown with the first set for context):

No kidding. Did you read my post?

You have change the numbers in the other two character sets if you use blocks and boxes.

So, what you're saying is that if you use Custom Character 0 on those displays, everything goes crazy?
Displaying the wrong characters on the wrong lines.

And by just not using Cust. Char 0, everythings AOK?
On both of your dispays?

That's a new one ... but it sounds typical for Newhaven.

Yup. I tried this on both displays with different programs. Whenever a 0 is used, the display gets all wacky. It will not only display the characters on the wrong line, the entire OLED displays wacky stuff. (I took two crappy cell phone pics of the differences). You also have to change the LCDOUT commands too. If you don't, it will still work but the box won't be filled out completely.

I tested it a bunch of different ways and I couldn't make it fail. Perhaps I didn't test every single mode but what I did test (what I normally use) worked perfectly!