Test and debug features included in
the Gearbox are PRBS pattern generation and checking, eye monitoring on
all data receive interfaces, programmable loopbacks, as well as JTAG.
Every port on the chip is equipped with an eye monitor. All features are
accessed through an IEEE standard MDIO control interface.
The other Gearbox
BCM82790 features include:
ten lane-to-four lane Gearbox via IEEE 802.3ba Clause 83 PMA
ten lanes to four lanes Gearbox via ITU OTL4.4
eye mapper on each high-speed receiver (14 total)
preemphasis and adaptive receive equalization on all data I/Os
adaptive 25 Gbps receivers with 30 dB EQ
adaptive 10 Gbps receivers with 27 dB EQ
drivers individually configurable voltage swing and preemphasis
IEEE 802.3bj Clause 91 Forward Error Correction (FEC) and bypassable.
and system-side loopbacks
1EEE802.3ap CL73 auto-negotiation
CL92 100G Ethernet (CR4) Tx Training
CL93 100G Ethernet (KR4) Tx Training
Ethernet: 156.25/161.13/312.50/322.26/625.00/644.50 MHZ reference clocks
two-wire serial interface (BSC) support for external modules.
module, I/O control signals for CFP2,CFP4,and QSFP28
interface-compliant to IEEE 802.3ae Clause 45
diagnostics includes nonintrusive eye mapping and BER with PRBS
signalling at 1.2V or 3.3V
pin with an array of maskable interrupt events
internal eye mapper on each lineside and system-side receiver
16-bit pattern generators and checkers on both line and system sides
master interfaces for QSFP28 control
for QSFP28 control pins
10x10GbE to 4x25GbE CAUI Functional Block
Gearbox Functional Block