Anyone ever decoded CAN on a PIC?

[Tom Gonser]

All:

Compressed Alphanumeric Code, or CAN code, allows a 16 bit value to represent 3 characters from the set A-Z, 0-9 and the colon, period and dollar sign symbols.

HEX CAN HEX CAN HEX CAN
0 0 0
640 A 28 A 1 A
C80 B 50 B 2 B
12C0 C 78 C 3 C
1900 D A0 D 4 D
1F40 E C8 E 5 E
2580 F F0 F 6 F
2BC0 G 118 G 7 G
32C0 H 140 H 8 H
3800 I 168 I 9 I
3E40 J 190 J A J
4480 K 1B8 K B K
4B00 L 1E0 L C L
5140 M 208 M D M
5780 N 230 N E N
5DC0 O 258 O F O
6400 P 280 P 10 P
6A40 Q 2A8 Q 11 Q
7080 R 2D0 R 12 R
76C0 S 2F8 S 13 S
7D00 T 320 T 14 T
8340 U 348 U 15 U
8980 V 370 V 16 V
8FC0 W 398 W 17 W
9600 X 3C0 X 18 X
9C40 Y 3E8 Y 19 Y
A280 Z 410 Z 1A Z
A8C0 0 438 0 1B 0
AF00 1 460 1 1C 1
B540 2 488 2 1D 2
BB80 3 4B0 3 1E 3
C1C0 4 4D8 4 1F 4
C800 5 500 5 20 5
CE40 6 528 6 21 6
D480 7 550 7 22 7
DAC0 8 578 8 23 8
E100 9 5A0 9 24 9
E740 : 5C8 : 25 :
ED80 . 5F0 . 26 .
F3C0 $ 618 $ 27 $

Sample Conversions For "EVI"

To convert to CAN code from ASCII, locate the letter in the tables from left to right, and summing the values indicated. For example:

E = 1F40
V = 370
I = 9
22A9

To convert from CAN code to ASCII, start with the left most column and locate the largest value that does not exceed the CAN code value. Subtract the indicated value and repeat using the remainder for the second and last columns. For example, given the value #35A5:

35A5
-3200 H
3A5
-398 W
D M

The CAN code value #35A5 results in the letters HWM.

OK - So, for the really smart ones - can you hint at a structure that can figure that out in PicBasic? I really don't want to load the whole table into memory!!

I need to take in the CAN code, and return the 3-letter result....

TG

[EDWARD]

you might what to decode the table in like a visual basic program then copy it into picbasic. those are more powerful for database projects. you can load a txt file as a .dat file into vb6 and sequentially read a set of numbers, perform alg and repeat.
if im way off sory, i didnt know of CAN.

i have vb6 progs i made but they only read comma seperated values and im not sure how big your table is and if putting comma in there would be an option.

or



is the reason you used CAN so that you could compress your data down? and you need it t reside in the memory, but ascii wouldnt fit? or is it like a learning project?

[Tom Gonser]

' Read the TracID into the 3 letters represented

16 bits are in SSD1-SSD4:

SSD4= (ssmax[1]>>4)
SSD3= (ssmax[1] & $f)
SSD2= (ssmax[0]>>4)
SSD1= (ssmax[0] & $f)
TracID_D=(ssd4*4096)+(ssd3*256)+(ssd2*16)+ssd1 ' convert to dec

TC1=(TracID_D/1600)
Select Case TC1
case 0
TracID1 = " "
case TC1 < 27 'A-Z
TracID1 = TC1 + 64
case TC1 < 37 '0-9
TracID1 = TC1 + 21
case 37
TracID1 = ":"
case 38
TracID1 = "."
case else
TracID1 = "$"
End Select

t2=TracID_D-(TC1*1600)
TC2=t2/40
Select Case TC2
case 0
TracID2 = " "
case TC2 < 27 'A-Z
TracID2 = TC2 + 64
case TC2 < 37 '0-9
TracID2 = TC2 + 21
case 37
TracID1 = ":"
case 38
TracID1 = "."
case else
TracID1 = "$"
End Select

TC3=t2-(TC2*40)
Select Case TC3
case 0
TracID3 = " "
case TC3 < 27 'A-Z
TracID3 = TC3 + 64
case TC3 < 37 '0-9
TracID3 = TC3 + 21
case 37
TracID1 = ":"
case 38
TracID1 = "."
case else
TracID1 = "$"
End Select


TracID1, TracID2, TracID3 will be the 3 letters..

TG