# Cadence GEM/MACB - emllGEM

The parameters to the Real-time Ethernet Driver GEM are setup-specific. The function `CreateLinkParmsFromCmdLineGEM()` in [`EcSelectLinkLayer.cpp`](_downloads/bf62c71a4a7e317930818b9da4a9815c/EcSelectLinkLayer.cpp) demonstrates how to initialize the Real-time Ethernet Driver instance.

### struct EC_T_LINK_PARMS_GEM

### Public Members

### [EC_T_LINK_PARMS](emll_init.html.md#_CPPv415EC_T_LINK_PARMS) linkParms

Common link parameters. Signature must be set to EC_LINK_PARMS_SIGNATURE_GEM. 

### [EC_T_GEM_RXSOURCE](#_CPPv417EC_T_GEM_RXSOURCE) eRxSource

Source of RX clock, control and data signals 

### [EC_T_DWORD](api.html.md#_CPPv410EC_T_DWORD) dwPhyAddr

PHY address 

### [EC_T_DWORD](api.html.md#_CPPv410EC_T_DWORD) dwRxInterrupt

Receive interrupt number (IRQ) 

### [EC_T_BOOL](api.html.md#_CPPv49EC_T_BOOL) bUseDmaBuffers

Use buffers from DMA (EC_TRUE) or from heap for receive. AllocSend is not supported when EC_FALSE. 

### [EC_T_BOOL](api.html.md#_CPPv49EC_T_BOOL) bNoPhyAccess

EC_FALSE: Link layer should initialize PHY and read link status (connected/disconnected). EC_TRUE: Client is responsible of PHY initialization and clock initialization. 

### [EC_T_BOOL](api.html.md#_CPPv49EC_T_BOOL) bUseGmiiToRgmiiConv

Use XILINX GMIITORGMII Converter (EC_TRUE) 

### [EC_T_DWORD](api.html.md#_CPPv410EC_T_DWORD) dwConvPhyAddr

PHY address used to communicate with converter. In Linux doc it is named “reg”. 

### [EC_T_DWORD](api.html.md#_CPPv410EC_T_DWORD) dwTxDmaDesCnt

Transmit DMA descriptor buffer count. Must be a power of 2, maximum 256. 

### [EC_T_DWORD](api.html.md#_CPPv410EC_T_DWORD) dwRxDmaDesCnt

Receive DMA descriptor buffer count. Must be a power of 2, maximum 256. 

### [EC_T_GEM_TYPE](#_CPPv413EC_T_GEM_TYPE) eGemType

System on Chip type 

### [EC_T_PHYINTERFACE](emll_init.html.md#_CPPv417EC_T_PHYINTERFACE) ePhyInterface

PHY connection type 

### [EC_T_BOOL](api.html.md#_CPPv49EC_T_BOOL) bNoPinMuxing

No clock configuration and pin muxing 

### EC_T_GEM_CLK_DIV_TYPE eClkDivType

Change Ref Clock settings 

### [EC_T_BOOL](api.html.md#_CPPv49EC_T_BOOL) bNotUseCacheSync

Default use of CacheSync EC_FALSE, don’t call CacheSync on older systems EC_TRUE 

### enum EC_T_GEM_RXSOURCE

*Values:*

### enumerator eGemRxSource_MIO

MIO as source for RX clock, control and data signals 

### enumerator eGemRxSource_EMIO

EMIO as source for RX clock, control and data signals 

### enum EC_T_GEM_TYPE

*Values:*

### enumerator eGemType_Zynq7000

Xilinx Zynq 7000 

### enumerator eGemType_ZynqUltrascale

Xilinx Zynq Ultrascale 

### enumerator eGemType_BCM2712

Broadcom BCM2712, Raspberry Pi 5 

### enumerator eGemType_PolarFire

Microchip PolarFire SoC