wiki:HardwareUsersGuides/FMC-RF-2X245/MGTs

FMC-RF-2X245 User Guide: MGT Interfaces

The FMC standard dedicates pins for 10 multi-gigabit transceivers (MGTs), labeled DP[0:9] in the standard. The Mango FMC-RF-2X245 module connects 4 transceivers to SATA connectors.

Important: the FMC-RF-2X245 module MGT interfaces are not intended for connections to SATA devices (like hard drives). While it may be possible to implement a standard SATA host in the FPGA and connect it to an SATA target via the FMC-RF-2X245 module, this is not something we have tested. These interfaces are intended for connections between WARP v3 kits, each equipped with FMC-RF-2X245 modules.

Connectors

The FMC-RF-2X245 module has four SATA connectors. Each connector is tied to one transceiver on the FMC connector. This connection consists of 4 data signals (DPx_M2C_[p,n], DPx_C2M_[p,n]). The SATA connector ground pins are tied to the PCB ground planes, which are tied to the FMC ground pins.

Two of the SATA connectors are wired as hosts; the other two are wired as targets. This allows two FMC-RF-2X245 modules to be connected via a standard (non-crossover) SATA cable.

All Tx and Rx data lines for all 4 connectors are AC-coupled on the FMC-RF-2X245 module with 0.1µF capacitors.

The SATA connectors are labeled on the FMC-RF-2X245 PCB as A, B, C and D. The table below lists the mapping of SATA connector to FMC DP and to the corresponding GTX instance when used on a WARP v3 kit.

Connector Pinout FMC DP WARP v3 GTX
A Host DP7 GTX3_115 / GTX_X0Y15
B Host DP4 GTX2_115 / GTX_X0Y14
C Target DP6 GTX1_115 / GTX_X0Y13
D Target DP5 GTX0_115 / GTX_X0Y12

Clocking

The FMC standard requires FMC modules which use the DP signals also provide the reference clock for the FPGA transceivers. There are two dedicated differential clocks on the FMC header for these signals, labeled GBTCLK0_M2C and GBTCLK1_M2C.

GBTCLK0_M2C: the FMC-RF-2X245 module has an LVDS oscillator tied to GBTCLK0_M2C. Modules are currently assembled with a 156.25MHz oscillator.

GBTCLK1_M2C: the FMC-RF-2X245 module connects this clock signal to MMCX jacks (one each for +/-). This allows an external clock source to be used as the MGT reference clock. By default the MMCX connectors are not mounted but can be added at J4/J5 if needed.

Last modified 6 years ago Last modified on Jan 16, 2013, 5:10:21 AM