2.11.5 Silicon Explorer II Probe Interface

Silicon Explorer II is an integrated hardware and software solution that, in conjunction with the Designer tools, allows users to examine any of the internal nets (except I/O registers) of the device while it is operating in a prototype or a production system. The user can probe up to four nodes at a time without changing the placement and routing of the design and without using any additional device resources. Highlighted nets in Designer’s ChipPlanner can be accessed using Silicon Explorer II in order to observe their real time values.

Silicon Explorer II's noninvasive method does not alter timing or loading effects, thus shortening the debug cycle. In addition, Silicon Explorer II does not require relayout or additional MUXes to bring signals out to external pins, which is necessary when using programmable logic devices from other suppliers. By eliminating multiple place-and-route program cycles, the integrity of the design is maintained throughout the debug process.

Each member of the Axcelerator family has four external pads: PRA, PRB, PRC, and PRD. These can be used to bring out four probe signals from the Axcelerator device (note that the AX125 only has two probe signals that can be observed: PRA and PRB). Each core tile has up to two probe signals. To disallow probing, the SFUS security fuse in the silicon signature has to be programmed (see Special Fuses).

Silicon Explorer II connects to the host PC using a standard serial port connector. Connections to the circuit board are achieved using a nine-pin D-Sub connector (see Figure 1-9). Once the design has been placed-and-routed, and the Axcelerator device has been programmed, Silicon Explorer II can be connected and the Explorer software can be launched.

Silicon Explorer II comes with an additional optional PC hosted tool that emulates an 18-channel logic analyzer. Four channels are used to monitor four internal nodes, and 14 channels are available to probe external signals. The software included with the tool provides the user with an intuitive interface that allows for easy viewing and editing of signal waveforms.