214
Network-on-Chip
FOC_1
(4–5 coding)
FOC_2
(4–5 coding)
FOC_8
(4–5 coding)
32 bits
40 bits
Figure 7.16
Combining adjacent subchannels in FOC encoding.
TABLe 7.4
Truth Table of FTC 3–4
Data Bits
Code Bits
D2 D1 D0 C3 C2 C1 C0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
0
0
0
0
1
1
1
0
1
0
1
1
1
1
1
0
0
0
0
1
0
0
1
0
0
1
1
1
0
1
1
boundaries between them. Consequently, a 32-bit uncoded link will be converted to a 53-bit coded link as shown in Figure 7.17. By contrast, shielding
requires a 63-bit link.
7.4.2.1.3 Forbidden Pattern Coding
The same reduction of the coupling factor as for FTCs (p = 2) can be achieved
by avoiding 010 and 101 bit patterns for each of the code words. This condition is referred to as forbidden pattern condition, and the corresponding CAC
is known as a forbidden pattern code (FPC) (Sridhara and Shanbhag 2007).
The simplest FPC code is realized by duplication, where each data bit is transmitted using two adjacent wires. Considering a 4-bit subchannel, the coding