**** BEGIN LOGGING AT Tue Mar 06 02:59:58 2012 Mar 06 16:22:44 has anyone been able to communicate with a pico chip pc202? i have a device that i am trying to communicate with that chip, but have been unable to figure out any of the communication protocols. from looking at the dev board, it seems like there are multiple jtac outputs, which align to some pads on the board i have. currently have a logic analyzer connected, but haven't gotten anything useful... Mar 06 20:41:24 http://hackingbtbusinesshub.wordpress.com/2012/01/26/discovering-jtag-pinouts/ Mar 06 20:41:37 @ wuntee Mar 06 20:44:39 roxfan: thanks. so, after reading about jtag all day, i have a few questions maybe someone can answer. as i understand jtag is a serial in/out communication with a clock. if that is the case, can't you simply connect the correct pins to a ftdi 3.3 serial to usb type cable? what are things like http://www.segger.com/cms/j-link-edu.html and the associated adapters for? Mar 06 20:45:26 serial to usb is for UART communication only Mar 06 20:46:20 jtag is syncronous serial, and it has an extra pin (TMS) in addition to clock, input and output Mar 06 20:47:07 so, in the case of that segger j-link, what does the hardware actually do? why is it required? Mar 06 20:47:23 it's not "required" Mar 06 20:47:48 you can get cheaper ones that basically let you bitbang the pins from pc Mar 06 20:48:01 but that's quite slow, especially with the usb latency Mar 06 20:48:57 jlink and similar probes do all the low-level state machine stuff inside, so pc only has to send high-level commands Mar 06 20:48:58 the device/cable are fairly inexpensive. i am more trying to understand what their functionality is in order to understand if i need them before purchasing.. Mar 06 20:49:19 ahhh Mar 06 20:50:38 i think in should read more about jtag - thanks for the help though - any goto resources for a 101 on jtag? by past experiences has been with boards that have already been laid out for me - i.e.: solder this pin here, plug this here, run this software... Mar 06 20:55:41 dunno really... most of the official literature concentrates on boundary scan (testing interconnects etc) Mar 06 20:56:20 http://elinux.org/JTAG try some links maybe Mar 06 20:58:10 thanks - anything helps. Mar 07 02:28:30 grab the book The Boundary Scan Handbook by Kenneth P Parker. Mar 07 02:28:44 i have 2nd ed so only gies up to 1149.4, not 1149.16 Mar 07 02:28:47 6 **** ENDING LOGGING AT Wed Mar 07 02:59:58 2012