Difference: DCC2InputDataLink ( vs. 1)

HTR Input	Function <-- -->	Notes
5	x	Not used due to PCB layout crosstalk issue (ignored by DCC)
13	S1	Framing bit, set to '1' for header and trailer words only
23	P	Parity bit
15	H4	Hamming code bit 4
7	H3	Hamming code bit 3
3	H2	Hamming code bit 2
1	H1	Hamming code bit 1
0	H0	Hamming code bit 0
22	D9	Data bit 9
12	D8	Data bit 8
11	D7	Data bit 7
10	D6	Data bit 6
9	D5	Data bit 5
8	D4	Data bit 4
6	D3	Data bit 3
21	D2	Data bit 2
20	D15	Data bit 15
19	D14	Data bit 14
18	D13	Data bit 13
17	D12	Data bit 12
16	D11	Data bit 11
14	D10	Data bit 10
4	D1	Data bit 1
2	D0	Data bit 0

Bits 0-23 only are connected on the DS90CR285 transmitter on the HTR (See HTR Schematic excerpt).

Of the 24 bits, 16 are used for data. Of the remaining 8, originally two were used for framing bits (named S0, S1) and the other 6 were for ECC coding. The original format is described here. This was changed due to the PCB layout problem described here in ~2008.

In the DCC2, a Channel Link receiver is not used but instead a deserializer implemented in a Spartan-3 FPGA.

-- EricHazen - 09 Oct 2012