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Altera_Forum
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18 years ago

Missing virtual jtag documentation

Hello, I started to use the sld_virtual_jtag Megafunction for low level debugging puposes, using Tcl interface with quartus_stp. Now I'm considering possible operation with non-Altera JTAG inte...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

Thanks for your help, I got it to work!

However, I am running into a different problem. Like I mentioned earlier, I am using the VJI to program a flash device, so I am shifting values into my BSR (Boundary Scan Registers) that are connected to the SCK,SI,CS and SO pins of my flash device. So basically, I am continuously shifting a value of 0 and 1 into the BSR cell that is connected to the SCK. Also, shifting my data to the BSR cell to the SI pin and etc.

Now, I created a script which basically contains the device_ir and device_dr shift commands. When I run this script and try to measure the frequency of the BSR register that is connected to SCK, I am getting like 250 Hz. I tried to measure the TCK coming out of the VJI as well and that is running at around 1 MHz.

Do you guys know why there is such a significant decrease in the frequency of my SCK. I only have 3 boundary scan cell (one for SCK, one for SI, and one for CS). Is this decrease in speed due to the device_dr shift command? I have attached the RTL map for my design.

Please Help,

Thanks