NB2DSK01 - Board Communications
Communications between the various devices within the system makes extensive use of the technology defined by IEEE Standard 1149.1 – commonly referred to as JTAG. The Desktop NanoBoard NB2DSK01 is connected to your PC using either a USB or parallel connection. When you start Altium Designer, a driver is loaded that configures the relevant port (USB or parallel) to run as a single multiplexed JTAG link between the NB2DSK01 and the PC.
Local to the NB2DSK01 itself, there are in fact multiple JTAG 'chains' present. These chains provide the communications paths between the various devices in the system. Within Altium Designer, interaction with these chains is performed through a Devices view (Figure 1), accessed by choosing View » Devices Views from the main menus. A view can be configured to show:
- All hardware connected to the PC (via USB and Parallel ports) in the same view
- Hardware connected to the PC via a Parallel port only
- Hardware connected to the PC via USB ports over multiple views – one view per USB port.
A Devices view presents three JTAG chains, which collectively show all JTAG-compliant devices attached to the system on the nominated port (or ports). Each device in each chain is represented by its appropriate icon. Controls for a device can be accessed through interaction (double-click, right-click) with its icon, giving full control over all JTAG devices in the system.
Use the following linked pages to take a closer look at the three chains presented in a Devices view, as well as information on Altium's proprietary communications protocol – NanoTalk.