Products > Test Equipment
Sniffing the Rigol's internal I2C bus
qwertymodo:
That depends entirely on how fast you set your JTAG dongle to communicate. You need the LA to be set to at least twice as fast as the JTAG bit rate, ideally more like 4-8x, and then number of samples really comes down to the memory limitations and how much data you want to sift through.
psysc0rpi0n:
--- Quote from: qwertymodo on September 23, 2016, 07:38:47 pm ---That depends entirely on how fast you set your JTAG dongle to communicate. You need the LA to be set to at least twice as fast as the JTAG bit rate, ideally more like 4-8x, and then number of samples really comes down to the memory limitations and how much data you want to sift through.
--- End quote ---
And how do I know JTAG speed? Where do I set it?
qwertymodo:
There's an openocd command for setting the speed.
psysc0rpi0n:
--- Quote from: qwertymodo on September 23, 2016, 07:48:26 pm ---There's an openocd command for setting the speed.
--- End quote ---
But can I use my Logic Analyser to set the speed of JTAG or if I use J_Link/OpenOCD and run it, will it detect the JTAG and be able to set the speed? Sorry, I'm just starting with this! It's the first time I deal with JTAG!
I have some doubts about how to connect the LA to the JTAG header.
I have this clone of Saleae Logic:
http://www.ebay.co.uk/itm/USB-saleae-Logic-Analyzer-Device-Set-USB-Cable-24MHz-8CH-24MHz-MCU-ARM-FPGA-/141694353386
It has 8 channels plus 2 GNDs.
I connected it like this:
Channel 0 --- TCK
Channel 1 --- TMS
Channel 2 --- TDI
Channel 3 --- TRST
Channel 4 --- 3V3/VREF (probably not needed)
Channel 5 --- TDO
Channel 6 --- SRST
Channel 7 --- Not Connected
Channel 8 --- GND
Channel 9 --- GND
But in the software, the SRST is not detected as the others are with the name of each pin. I'm not sure if it's normal...
Here is a picture of Saleae Logic Software:
qwertymodo:
The logic analyser won't control anything, it's just a passive listener, you need a jtag dongle compatible with openocd, which will control the actual jtag communication.
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