Difference: DCC2InputDataLink ( vs. 1)

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

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