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3 setting up serdes links, Figure 8-14, 122,912μs serdes frame – Artesyn ATCA-8310 Installation and Use (May 2014) User Manual

Page 435: Cpld and fpga, Releasing pcs quad reset, Waiting for tx pll to lock, Waiting for rx pll to lock

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CPLD and FPGA

ATCA-8310 Installation and Use (6806800M72E)

435

SERDES link. To identify a packet Start_of_Packet (K27.7 character) and End_of_Packet (K29.7
character) are used. This corresponds to a total packet size of 245824 bits. Since the
transmission duration of the 245760 bits on the TSIP side is 125 μs and on the SERDES side the
transmission of one packet takes 122,912μs regarding the 10B/8B encoding/decoding schema
there are still 2,088μs or 4176 bit remaining for idle time.

In the first realization step, an interface to 10 TI tomahawk DSPs each with two TSIP links
TSIP_TX (0..1)(0..9) and TSIP_TR (0..1)(0..9) will be implemented.

8.4.3.3

Setting up SERDES links

When the Reset control block releases the SERDES block reset line, a Serdes specific reset
sequence is processed which is indicated below:

Releasing PCS quad reset

Waiting for TX PLL to lock

Waiting for RX PLL to lock

Releasing channel specific resets for TX and RX direction

If the TX PLL or RX PLL remain in an unlock state (status can be read in SerDesTrmStatReg and
SerDesRcvStatReg), the serdes specific reset sequence will not finish. Setting
CompResReg:SrdsQuadReset first high, then low will retrigger the sequence.

Before data transmission can be started, a link state procedure forces the transmit and receive
state machines to a synchronous state. Therefore, the transmit state machine sends 100
consecutive COMMA characters followed by minimal 16 IDLE pattern and then starting
payload data transmission. The receive state machine itself expects 80 consecutive COMMA
characters, then entering idle state waiting for valid start of frame delimiters. Since transmit

Figure 8-14 122,912μs SERDES frame

Start of

packet

Suppl.

Info.

CRC

End of

packet

Speech information

8 bits

16 bits

32 bits

8 bits

245760 bits

4176 bits

125 μs frame of Speech information

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