Darrel's interrupts in a 7 segment display

[Darrel Taylor]

You guys always make me hungry. I LOVE spaghetti.
Just not in my code.

Main:
  FOR Value = 0 TO 999
    GOSUB SetDisp
    PAUSE 500
  NEXT Value
GOTO Main

'---[Set 7-seg patterns to WORD value]--------------------------------------
SetDisp:
  FOR Idx = 2 to 0 STEP -1
    Temp = Value DIG Idx
    LookUp Temp,[132,175,193,137,170,152,144,143,128,136,210,251],Temp
    SEGDEF(Idx) = Temp
  NEXT Idx
RETURN

'---[TMR1 - interrupt handler]----------------------------------------------
DISP:
  T1CON.0 = 0                  ; stop timer
  TMR1H = %11111100
  TMR1L = %00011111
  T1CON.0 = 1                  ; restart timer

  PORTE = %111                 ; turn off all digits to prevent ghosting
  PORTC = SEGDEF(digitloop)    ; put segment pattern to pin
  PORTE = ~(DCD digitloop)     ; turn on the digit

  digitloop = digitloop + 1    ; prepare for next digit
  IF digitloop = 3 then digitloop = 0
@ INT_RETURN

Completely untested ...

[nomad]

WOW... how simple to put the digitloop at the end, MUCH cleaner. less if'ing
was looking at it backwards lol , maybe I should try standing on my head..

and I started to do a loop (for) deal, but cant use val(x) in the lookup, and went all off the other way. lol.. shoulda figured out/stuck with the original idea.


THANKS! looks shweet cant wait to test

Think you solved both our problems!

[ardhuru]

Wow, worked the first time, Darrel.

Now, if I want to bit bang (I've already commited the hardware UART to something else) a couple of parameter values over the serial port, where in the code you've shown would the line go?

I've been struggling with this, with no success; or is this normal when one is using TMR0?

Regards,

Anand

[ardhuru]

[QUOTE=ardhuru;70828]; or is this normal when one is using TMR0?

/QUOTE]

Sorry, TMR1, I mean.

[Darrel Taylor]

Wow, worked the first time, Darrel.

Great! I guess my internal simulator is still working.

a couple of parameter values over the serial port

If it's only a couple values every now and then, just turn off the interrupts before using the SEROUT? statement.
Depending on the baudrate and amount of data, it may cause a small blink in the display.
<br>

[Charles Linquis]

If you set your interrupt time to 1.5mSec or so, you can send one character at 9600 baud between interrupts. Just don't try to do too much else in that period!

[boroko]

Hi all,
I'm having trouble understanding something in this example code. Maybe someone can explain.

Main:
  FOR Value = 0 TO 999
    GOSUB SetDisp
    PAUSE 500
  NEXT Value
GOTO Main

'---[Set 7-seg patterns to WORD value]--------------------------------------
SetDisp:
  FOR Idx = 2 to 0 STEP -1
    Temp = Value DIG Idx
    LookUp Temp,[132,175,193,137,170,152,144,143,128,136,210,251],Temp
    SEGDEF(Idx) = Temp
  NEXT Idx
RETURN

The biggest question is why is there 12 data points in the table? I am assuming that the actual numbers are because of the wiring of the digits with this specific LED as I can not figure out a segment pattern. After that, I fall down on why 12 instead of 8 unless it involves positioning the decimal point somehow. I wonder, if with the original wiring, this would be clearer to me. I would think that you would line up the segments in order with the port pins in order.

Thanks
Mark

[boroko]

Another observation that this is a specific solution to the OP's issue is that can't be just cut-n-pasted without thinking it through:

PORTE = %111                 ; turn off all digits to prevent ghosting
  PORTC = SEGDEF(digitloop)    ; put segment pattern to pin
  PORTE = ~(DCD digitloop)     ; turn on the digit

my application is common cathode and it uses a ULN2803 as a driver for the cathodes of the digits. If I hadn't looked at it and tried to understand it, I could have easily have turned on ALL BUT ONE of the displays instead of ONE AT A TIME. Mine is also, 8 digits, so it matters a bit more for the PIC pin. Not a complaint in any way, more of a way to close the loop for anyone looking at it later. BTW: very slick way to step through the digits. Learned something new today.
Mark

[EarlyBird2]

Hi all,
I'm having trouble understanding something in this example code. Maybe someone can explain.

Main:
  FOR Value = 0 TO 999
    GOSUB SetDisp
    PAUSE 500
  NEXT Value
GOTO Main

'---[Set 7-seg patterns to WORD value]--------------------------------------
SetDisp:
  FOR Idx = 2 to 0 STEP -1
    Temp = Value DIG Idx
    LookUp Temp,[132,175,193,137,170,152,144,143,128,136,210,251],Temp
    SEGDEF(Idx) = Temp
  NEXT Idx
RETURN

The biggest question is why is there 12 data points in the table? I am assuming that the actual numbers are because of the wiring of the digits with this specific LED as I can not figure out a segment pattern. After that, I fall down on why 12 instead of 8 unless it involves positioning the decimal point somehow. I wonder, if with the original wiring, this would be clearer to me. I would think that you would line up the segments in order with the port pins in order.

Thanks
Mark

As I can not resist a challenge even if it is only an academic exercise to me.

------- GFEDCBA

0 132 10000100
1 175 10101111
2 193 11000001
3 137 10001001
4 170 10101010
5 152 10011000
6 144 10010000
7 143 10001111
8 128 10000000
9 136 10001000
F 210 11010010
- 251 11111011


Looking at the bit pattern for :-

0 the active segments are 0 and inactive 1 in a 0 the central cross bar is inactive therefore this is C
6 the only inactive segment is top right therefore this is E
5 the inactive segments are top right and bottom left so bottom left is D
9 confirms bottom left is D
3 top left and bottom left inactive so top left is A
2 top left and bottom right inactive so bottom right is G
7 top left centre bottom left and bottom inactive so bottom is B

which leaves F is the top segment giving this pattern

-F-
A E
-C-
D G
-B-


251 is the centre bar obviously used for - (minus)
210 converting the bit pattern gives F

Having decoded this pattern it makes no sense to me as the normal segment pattern is



Leaving the question why connect a 7 segment display in this no standard way?