A-20: 6—plus—2 conversion table – Rana Systems Elite Series User Manual

Page 311

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ELITE SERIES USER MANUAL

APPEN. A - DISK I/O

A total of 342 bytes are needed, shown by find-

ing the total number of bits (256 x 8 = 2048)

and dividing by the number of bits per byte

(2048 / 6 = 341.33). The transformation from the

six bit bytes to valid data bytes is also

performed by a one to one mapping, illustrated

in the figure below.

Again, the stream of data bytes written to the

diskette are a product of exciusive-ORs, similar

to the 5-plus-3 technique shown above.

Nybblized Data = Disk Byte

00 = 96

10 = B4

20 = D6

30 = ED

01 = 97

11 = B5

21 = D7

31 = EE

02 = 9A

12 = B6

22 = D9

32 = EF

03 = 9B

13 = B7

23 = DA

33 = F2

04 = 9D

14 = B9

24 = DE

34 = F3

05 = 9E

15 = BA

25 = DC

35 = F4

06 = 9F

16 = BB

26 = DD

36 = F5

07 = A6

17 = BC

27 = DE

37 = F6

08 = A7

18 = BD

28 = DF

38 = F7

09 = AB

19 = BE

29 = E5

39 = F9

0A = AC

lA = BF

2A = E6

3A = FA

0B = AD

lB = CD

2B = E7

3B = FB

0C = AE

1C = CD

2C = E9

3C = FC

0D = AF

1D = CE

2D = EA

3D = FD

0E = B2

lB = CF

2E = EB

3E = FE

0F = B3

1F = D3

2F = EC

3F = FF

* AA and D5 are reserved bytes.

F i g . A - 2 0 : 6 - p l u s - 2 C o n v e r s i o n T a b l e

P a g e A - 4 0

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