jtag_uart bitrate

[Altera_Forum]

Hi, 

what is the theoretical maximum bit rate for jtag_uart ip in sopc? assuming no other IP is using the usb-blaster cable.  currently I'm sending data from NiosII to computer using jtag-uart and jtag-atlantic. however I need to know the exact bit rate.  Thanks Adel

[Altera_Forum]

Exact is a strict word. You'll find an estimation of 0.5 to 1 Mbps for the high speed image download demo example: 

http://www.nioswiki.com/exampledesigns/highspeedimagedownloaddemo

[Altera_Forum]

thanks for your prompt response. 

I tried to push jtag-uart to see if I could squeeze any more bits out of it. at best, it gives around 150-160KB which is equals to 1.2-1.3 Mbps.  it's roughly 80% utilization of usb-blaster cable considering the bandwidth of USB 1.0 is ~1.5Mbps. (usb-blaster is usb1, right?) Nios2/f is clocked at 150MHz on a cyclone III fpga (sg=2). jtag-uart has 1k buffer. also all ip-cores that might use the usb-blaster (like signal tap) are turned off.

[Altera_Forum]

USB Blaster is uses Full Speed USB (FTDI FT245), but the JTAG speed is limited to 6 MHz by the USB Blaster Hardware. Furthermore there is a considerable overhead of the virtual JTAG protocol transferring the UART payload with a word length of 8-Bit only.