ESC Boston exhibitor touts JTAG to boost NVM programming speed
Although originally conceived as a means of testing component interconnectivity on a printed-circuit board, boundary-scan technology also offers a window into the inner workings of a chip. That window also provides a means of programming NVM (nonvolatile memory). However, the traditional method of programming NVM via the boundary-scan TAP (Test Access Port) can be slow. Simply reading every location in a 16-bit wide, 128-Mbit flash device can take more than eight minutes, and programming the device can take much longer, reports boundary-scan company XJTAG.
Fortunately, a design incorporating NVM is likely to include an embedded processor that has direct access to the NVM. An ARM Cortex M3 processor, for example, includes a “Memory Access Port” for that purpose. Furthermore, an embedded processor is likely to include a JTAG interface that’s used for processor debug. Designers can leverage the combination of direct memory access and JTAG debug interface to significantly improve NVM programming speed. Designers can exert similar leverage on PLD-based designs if the PLD has full access to the NVM and is also programmable via the JTAG chain.
XJTAG reports that Micron has chosen to employ such leverage to speed the programming of its PCM (phase change memory) nonvolatile devices. Engineers from XJTAG were able to employ the XJFlash capability of XJTAG’s boundary scan system to reduce the total programming time of a 128-Mbit PCM device to less than 20 seconds, with an average write-cycle time of less than 2 μs.
You can read a case study that summarizes the application of XJFlash to Micron’s application as well as a white paper that details how to apply boundary-scan technology to speed NVM programming in processor- or PLD-based designs, with specific emphasis on an example based on the Micron-supplied demo board that has two JTAG chains: one with an Intel/Marvell PXA270 processor and the other with a Xilinx Spartan 3 FPGA. XJTAG will highlight NVM programming and other boundary-scan applications September 26-29 at the Embedded Systems Conference Boston.
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Brandywine commented:
Well mcaamadia nuts, how about that.
