Setting DCC parameters

Ethernet bridging works by examining incoming packets at debug hardware, then deciding which are destined for debug hardware itself and which are destined for the target. To do this, debug hardware must know the IP address, subnet mask and default gateway parameters for the target. These parameters are normally determined through DHCP, where the target asks for a configuration, and one is supplied by a server over the network. In this case, debug hardware is able to intercept the incoming DHCP packet containing the parameters and configure itself appropriately. It is, however, possible to configure a target with a static IP address. In this case there is no DHCP transaction to intercept, and debug hardware has no way of determining the target configuration. You must set these parameters in debug hardware for correct operation.

You can configure DCC Ethernet bridging with the rvigdbconfig command, and you must set the appropriate parameter when using DCC mode.

If you use rviload, you must set the DCC mode to either VEC or VEP.


When Ethernet bridging is running, normal LAN services are accessible (including DHCP and NFS).

Show/hideExamples of setting DCC parameters

rvigdbconfig -f rvi.rvc -d 1:2

sets device 1 (the first device on the scan chain) to DCC mode 2.

Additional devices are configured in a similar way. For example:

rvigdbconfig -f rvi.rvc -d 1:2 -d 2:2

configures devices 1 and 2 to mode 2.

The IP parameters for static IP configurations are set up in the following way:

rvigdbconfig -f rvi.rvc -d 1:2 -s 1:

This configures device 1 to use DCC mode 2 with IP address, subnet mask, and default gateway This format can be used to configure multiple processors if required. For example:

rvigdbconfig -f rvi.rvc -d 1:2 -d 2:2 -s 1: -s 2:

Show/hideSee also

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