Couple quick questions for 10 tile system and Flash size
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Folknology
- XCore Legend
- Posts: 1274
- Joined: Thu Dec 10, 2009 10:20 pm
Ah ok my bad, totally misunderstood, was thinking it was jtag signals being buffered onboard on a new XTAG 2 hardware that supported driving 128 L1s, Doh!!!...
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bearcat
- Respected Member
- Posts: 283
- Joined: Fri Mar 19, 2010 4:49 am
Thanks Redeye for your comments.
I will assume TDO -> TDI is ok without buffers. Even though the ouput impendance of a 4mA is in the range of 175ohms. That will save quite a few buffers.
I likewise have struggled with JTAG, reset, and treset. I have the added complication I can galvanically isolate one of the tiles. I have created a buffer board for the XTAG2 for this and added 24mA buffers, and almost have it right with a 2 tile system. Rev3 will hopefully take care of one last issue. On the product, I actually use a Microchip for reset, power, and power fail duty and on the Microchip I switch the output to an input after reset is applied so the XTAG2 can then drive the signals. I don't plug in the XTAG2 into the USB until I powered the board. 10 Tiles is more complicated.
I will assume TDO -> TDI is ok without buffers. Even though the ouput impendance of a 4mA is in the range of 175ohms. That will save quite a few buffers.
I likewise have struggled with JTAG, reset, and treset. I have the added complication I can galvanically isolate one of the tiles. I have created a buffer board for the XTAG2 for this and added 24mA buffers, and almost have it right with a 2 tile system. Rev3 will hopefully take care of one last issue. On the product, I actually use a Microchip for reset, power, and power fail duty and on the Microchip I switch the output to an input after reset is applied so the XTAG2 can then drive the signals. I don't plug in the XTAG2 into the USB until I powered the board. 10 Tiles is more complicated.