OK, all well and good, what is left to do, identify what sort of connector J5 actually is and make up a JTAG lead for it then connect it up and see if we are right. Some further technical info on TAP & JTAG can be found here worth a look at to illustrate some of the concepts behind JTAG. This case is compatible with all models of Raspberry Pi Zero including the. Combining the data we have then gives us the following table:- J5 Pin Information Pin No The underside of the pi zero case features a cut-out for the GPIO pins which. What is more the 5 pins we had not identified are broken out to pogo pin pads bang next to the footprint. Cross referencing the ground pin outs that we know from the Pi Zero we get a match. In fact it is so much the same it is also labelled J5. Fiddling with the board during one of many mental luls, I noticed the same mystery footprint on the board directly under the HDMI video connector.
RASPBERRY PI ZERO W PINOUT UNDERSIDE SERIAL
On the underside of the board there are also solder pads connected to power, ground, I2C, SPI and serial comms. It has eight active-low push-buttons connected to various GPIO pins. Embedding them irretrievably into other things. Score:Zero is a simple-soldering-kit-come-games-controller for the Raspberry Pi Zero. Purely as I tend to mostly use Pi2’s now and was using up any older ones that were lying around. Putting some time into a side project (building a Graphite graphing server) I was working with a Raspberry Pi B+. three 2×6 Digilent Pmod ports and provides access to additional I/O available via the Raspberry Pi 40- pin GPIO connector. But serendipity smiled upon me, in that way it never normally does. Normally at this point I would start on in with a multi meter or a scope and see what I could find out next. The up side is if they were JTAG, it would have to be dedicated pins, not GPIO pins, and therefore projects could be debugged even with a phat in place. As other than the reset they did not go to the GPIO pins I could rule out an easy hit as to what they were. I visually traced the connections and lost them in to the maze of CPU via’s. 1 is the Pi system reset or run pin as it is labeled, 4 and 7 are ground connections. Taking pin 1 to be the pin nearest the J5 ID we can see the footprint is for an 8 pin connector and the body or screen is not connected. Time then for some reverse engineering, first stop was a USB microscope and a look see for obvious pin functions, gotta tackle the low hanging fruit first. An extensive google around was surprisingly information free. Asking around amongst those who would know more than me about it (Not difficult to find) the hot favourite was a JTAG port but no one was entirely sure and there was no pinout. I have been puzzling over what it was intended for since getting my Pi Zero from Pimoroni. J5 is the mystery connector footprint on the bottom of the Pi Zero. J5 is alive, and is definitely not called johnny or a robot in a kids sci-fi film.
0 kommentar(er)
