Difference between XC-1A and XK-1A USB interface

Technical discussions related to any XMOS development kit or reference design. Eg XK-1A, sliceKIT, etc.
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DrNO
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Difference between XC-1A and XK-1A USB interface

Post by DrNO »

Hello All,
I had a quick question. I was going through the schematics for the XC-1A and the XK-1A/XTAG2 and was wondering why the XTAG requires an L1 chip and a USB controller whereas the USB interface for the XC-1A only uses an FTDI2232D chip (with integrated JTAG) to handle the communication.

My assumption is that the integration of JTAG into the FTDI chips came after the XTAG2 was created.

The main reason I'm asking is to see if there is any known difference in functions that an XTAG2 connection offers that the FTDI method does not (speed, debugging capabilities, etc.)

THANKS!


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XMatt
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Post by XMatt »

The XTAG-2 was developed to replace the use of FTDI with XMOS development boards. It offers a higher performing more flexible platform for the development tools interface. For JTAG the XTAG-2 gives a roughly 10x performance increase over the FTDI solution and also has spare capacity in the L1 to allow us to run the high speed data capture system that we use for Xscope in the development tools. Plus it is not 'fixed function' as with the FTDI device, it has a USB bootloader that allows the firmware to be configured at runtime so we can continue to increase the feature set of the device over time.
DrNO
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Post by DrNO »

I see! Thank you for the quick reply!!
DrNO
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Post by DrNO »

Ok so I guess my next logical question should be, do you have documentation of firmware for the XTAG2 module and the FTDI implementation of JTAG links? I would like to try and prototype a solution for each.
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Post by DrNO »

Does anyone know where to find the FTDI implementation of the XTAG2 firmware?
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Bianco
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Post by Bianco »

DrNO wrote:Does anyone know where to find the FTDI implementation of the XTAG2 firmware?
What do you mean? The FTDI chip does not run (an exposed) firmware.
It supports the JTAG standard by default, check the datasheet.
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Post by DrNO »

So is the FTDI chip just recognized by the VID and PID and the XMOS software takes care of interfacing with it?
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Bianco
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Post by Bianco »

yes
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