Smooth LED fading via PWM

[SteveB]

How about something like this:

Data 1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,3, _
  3,3,3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,5,5,5, _
  5,5,5,5,5,6,6,6,6,6,6,6,7,7,7,7,7,7,8,8,8,8,8,8,9,9, _
  9,9,10,10,10,10,10,11,11,11,11,12,12,12,13,13,13,13, _
  14,14,14,15,15,15,16,16,16,17,17,18,18,18,19,19,20,  _
  20,20,21,21,22,22,23,23,24,24,25,26,26,27,27,28,29,  _
  29,30,31,31,32,33,33,34,35,36,36,37,38,39,40,41,42,  _
  42,43,44,45,46,47,48,50,51,52,53,54,55,57,58,59,60,  _
  62,63,64,66,67,69,70,72,74,75,77,79,80,82,84,86,88,  _
  90,91,94,96,98,100,102,104,107,109,111,114,116,119,  _
  122,124,127,130,133,136,139,142,145,148,151,155,158, _
  161,165,169,172,176,180,184,188,192,196,201,205,210, _
  214,219,224,229,234,239,244,250,255
 
Smooth_fade:
    IF Count1 = 0 THEN 
         duty = 0
    ELSE
         IF Count1 < 26 THEN 
             duty = 1
         ELSE
             Read Count1-25, duty
         ENDIF
    ENDIF
    RETURN

WriteUserByte:
    WRITE 255, UserByte
    RETURN

ReadUserByte:
    READ 255, UserByte
    RETURN

Now you have the upper 25 EEPROM addresses to use. More space could be saved by using similar logic. But this hopefully gets the point across.

Good luck,
Steve

[SteveB]

My math was a little off, the line for the reading of the EEPROM should be

READ count1-26, duty

As a side note, you could make it really simple just by leaving the original table as-is and using this:

Smooth_fade: 
     IF Count1 = 0 THEN 
          duty = 0 
     ELSE 
          Read Count1, duty 
     ENDIF
RETURN

WriteUserByte: 
     WRITE 0, UserByte 
     RETURN

ReadUserByte: 
     READ 0, UserByte 
     RETURN

[HankMcSpank]

Bert.. re putting my table into program memory....it's still a work in progress and with only 400 bytes left...it only takes a couple of debug commands and I'm over the limit :-(

Byte_Butcher ...that's a good lead!

SteveB..... if I'm reading your code right, it's what Byte_butcher proposed? (& is good clawback of EEPROM)

I'll have a dabble later....many thanks for the input.

[SteveB]

SteveB..... if I'm reading your code right, it's what Byte_butcher proposed? (& is good clawback of EEPROM)

Yes, I took the suggestion from Byte_Butcher and fleshed it out a little.

[Byte_Butcher]

I've gotta go stack wood, so this is quickk and needs fixing, but this is the sort of thing I was thinking:

count = count + 1

If count < 33 then address = 1                   'all "counts" less than 33 point to address 1 
        if count < 1 then 
        address = 0                                     'unless count is 0. Then it points to address 0
        endif
        else address = count - 33                     'all counts above 33 get offset down so they pick up the sequence starting at address 2
endif

steve

edited to add:

Never mind, Steve B already did it.

[HankMcSpank]

IS there a rapido way of seeing the whole contents of EEPROM?

I'm storing a user determined byte, using this type of way..

DEFAULT_CONFIG  DATA 1
default_config_shadow var byte

default_config_shadow = 101010              '
WRITE default_config_shadow, default_config   'write the above to EEPROM

read default_config, default_config_shadow

DEBUG "def_shadow=",BIN default_config_shadow,13,10

then immdeiately afterwards, I lob another 254 bytes into EEprom too...

data   1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, _
1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, _
2,2,2,3,3,3,3,3,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4, _
4,4,5,5,5,5,5,5,5,5,6,6,6,6,6,6,6,7,7,7,7,7,7,8,8, _
8,8,8,8,9,9,9,9,10,10,10,10,10,11,11,11,11,12,12,12, _
13,13,13,13,14,14,14,15,15,15,16,16,16,17,17,18,18,18, _
19,19,20,20,20,21,21,22,22,23,23,24,24,25,26,26,27,27,28, _
29,29,30,31,31,32,33,33,34,35,36,36,37,38,39,40,41,42,42, _
43,44,45,46,47,48,50,51,52,53,54,55,57,58,59,60,62,63,64, _
66,67,69,70,72,74,75,77,79,80,82,84,86,88,90,91,94,96,98, _
100,102,104,107,109,111,114,116,119,122,124,127,130,133,136, _
139,142,145,148,151,155,158,161,165,169,172,176,180,184,188, _
192,196,201,205,210,214,219,224,229,234,239,244,250,255

just wondering how that all gets accounted for in EEprom, because I'm sure there's going to be some impact with the way I read that table type data back (eg is my user defined bye stored in EEPROM memory slot0, with the rest filling sequentially afterwards?) I was previously using a counter variable to look up/reference the the data stored in EEprom, but now I'm wondering if I need to offset it by 1? (due to the user stored byte in Eeprom too ....or can I store the one user defined byte at the end of the EEPRM...the last slot)


can I look at EEprom via the Pickit2 (I had a dabble but it wasn't obvious to read!)

Many thanks.

[HenrikOlsson]

Hi Hank,
First off all, it seems as if your WRITE statement is "reversed", you should do WRITE Adress, Value but to me it seems you have it the other way around, ie. writing whatever is in default_config to adress 42 (101010) when I think you actually want the value 42 written to adress 0, or 1 perhaps.

Second, I think (pretty sure) you should be able to read the EEPROM with the PICKit2, I only have a PK3 but if you can't figure it out I'll have a go later. With that said you could dump the EEPROM content over a serial line (if you have one) with something like:

Count VAR BYTE
Result VAR BYTE

For Count = 0 to 255
  Read Count, Result
  HSEROUT ["EEPROM Location: ", DEC3 Count, ": ", DEC RESULT,13]
NEXT

Third, if the first location in EEPROM (location 0) is reserved for that "userbyte" of data then you should start your DATA table with something like DATA @1, 1, 1, 1... Which will put the first entry at location 1 instead of location 0.

Finally, remeber that DATA isn't something that executes when the program runs, it only tells the compiler/assembler to put that data in the ".hex image" so that the programmer (your PICKit2) can program the values into EEPROM together with the actual program. WRITE, on the other hand is a runtime command and does write to the EEPROM when the program executes.

Hope that helps.
/Henrik.