Vtech introduces another VARON demo for SoC with arbitration method and 2 AXI interconnects. The bus master IPs with large amount of data transfers are connected to the main AXI. The CPU is connected to Port 0 with the highest priority and the sub AXI is connected to Port 5 with the lowest priority. We added a problem with the write from Sub AXI to DDR, which now becomes very slow.

Figure 1: Demo block diagram


VARON IP is configured to monitor ports of the sub AXI as Port Group 0, ports of the master side of the main AXI as Port Group 1 and ports of the slave side as Port Group 2.

All VARON performance charts are ready to display in a minute after loading the monitored data by VARON IP. There is no problem with the data transfer amount by port, but it turns out that the write transactions from the sub AXI take 7,000 clocks or more (versus expected several hundreds of clocks). It is easy and quick to specify the long-latency transactions and analyze the cause of the problem with Transaction Timing Chart where each read/write transaction is cycle-accurately mapped.

It is confirmed that the problem has been fixed by changing the arbitration method to switching priority every 500 clocks (from the fixed priority) for Ports 2 to Port5 of the main AXI.

This type of problem is much more difficult to identify with other vendors’ waveform-based analysis tools.  With Vtech’s VARON the problem and fix can be done in a short period of time.

Figure 2: Read/Write data transfer amount by port


Figure 3: Read/write latency Min/Average/Max by port


Figure 4: The detailed analysis on Transaction Timing Chart


Figure 5: Periodic priority change


VARON supports multiple AMBA protocols and platforms from simulator, hardware emulator, FPGA to ASIC by the single IP, and VARON is optimized especially for hardware emulation with very little speed degradation.

VARON also offers very short time to analysis in a few minutes and systematic analysis with rich portfolio of performance charts. Let VARON visualize analysis targets with the design criteria.

Schedule a VARON AMBA Performance Analysis demo or request a VARON free trial to:  vtech_usa_info@vtech-inc.co.jp