Revisions Affected

IWR2944 ES1.0, ES2.0

Details

Measurement Data Output (MDO) is used to capture the transactions on the bus connected from different interfaces of the IWR2944 device and transmit outside over Aurora LVDS Interface (4-data lanes). MDO is comprised of a sniffer, FIFO, and an aggregator. The MDO sniffer module is responsible for monitoring the hardware interfaces in the chip and capturing the transactions on the bus which are within the configured addressing region of interest.

Data loss due to overflow can occur at the sniffer. This overflow information is sent as an interrupt to the CPU and the Aurora Tx IP. A User-Flow-Control (UFC) packet is generated by the Aurora TX IP in case of a data overflow condition in order to notify the user of this error condition. This is an error scenario and is not expected to occur in normal transfer functionality. At this stage, the data integrity is already compromised.

Aurora IP only supports UFC packet generation as per Section 6.6 of Aurora 64B/66B Protocol Specification, i.e. the UFC header block precedes the UFC data blocks. Strict Alignment User Flow Control Stripping (refer to Section 6.7 of Aurora 64B/66B Protocol Specification) is currently not supported.

Workaround

For MDO, the input data rate should be less than the output data rate so as to keep the effective data rate well within reasonable limits to avoid any overflow condition altogether.