moyix
Posts: 2
Joined: Fri Sep 07, 2012 7:49 pm

S5 Pin Layout for ARM JTAG?

Fri Sep 07, 2012 7:57 pm

Hi,

I found this site ( https://github.com/dwelch67/raspberrypi ... er/armjtag ) with bare metal examples and an ARM JTAG sample, which says that the TMS pin comes from S5 pin 11. The only problem is, I don't know which pin on S5 is 11 – which one is pin 1? and which way does the numbering go?

Also, just to make sure I'm not completely off, S5 is the 30-pin connector between the HDMI and Ethernet ports, correct?

(I gather all this would be much simpler if I had a rev 2.0 board, but sadly I was an early adopter :) )

dwelch67
Posts: 954
Joined: Sat May 26, 2012 5:32 pm

Re: S5 Pin Layout for ARM JTAG?

Fri Sep 07, 2012 9:39 pm

Use an ohm meter to probe that connector. Find the end that has either vcc or ground, and/or find all the vcc and grounds so you can be sure you understand the orientation.

I dont remember off hand without probing looking but I think that connector is such that the legs that stick out either side are connected (it is a single row thing not a double row thing). I connect my wire on the hdmi connector side of the s5 connector. Looking down on the board with the hdmi connector up or above the S5 connector, the pin in question is on the left half/side of that connector. We have a nice soldering station at work with a microscope, my eyes are not that young anymore, I add a little more solder to that pin without bridging to the neighbors. Then put the wire on it and add hot glue or something on top of all that to help it stay on mechanically.

The new rev of the board when it comes out will have this signal on the main connector so we wont have to do this after that.

David

moyix
Posts: 2
Joined: Fri Sep 07, 2012 7:49 pm

Re: S5 Pin Layout for ARM JTAG?

Fri Sep 07, 2012 9:45 pm

Thanks! After checking the schematic and using an ohm meter as you suggested, I found the right pin. Unfortunately, after several attempts I've only succeeded in bridging the nearby pins together, so I think I may have to wait for the new board :p

One question though -- would it be easier to find a flat ribbon cable to use in the S5 connector and then attach to that?

dwelch67
Posts: 954
Joined: Sat May 26, 2012 5:32 pm

Re: S5 Pin Layout for ARM JTAG?

Sat Sep 08, 2012 12:46 am

I dont know if that is easier or not, I would guess it is, at least if you mess up the cable you can get another, messing up the board...well you get another board...I didnt try the cable approach myself, those connectors are delicate as well, so dont be too rough...

User avatar
hellonearthis
Posts: 22
Joined: Sun Aug 05, 2012 6:35 pm

Re: S5 Pin Layout for ARM JTAG?

Thu Sep 13, 2012 9:47 pm

Would it be easier to patch into the HDMI cable to access that pin?
Or Solder onto the tab in rPi HDMI socket, much larger solder area than there and if it was done at the back would not worry cable.

Still at the price, I may just get a 2.0 when they can be ordered with certification that they are 2.0s

dwelch67
Posts: 954
Joined: Sat May 26, 2012 5:32 pm

Re: S5 Pin Layout for ARM JTAG?

Fri Sep 14, 2012 1:37 am

Not a bad plan you can get by with using a serial bootloader until 2.0 comes out. Have to do more power cycles, but fewer/no sd card insertion cycles.

David

amitdpg
Posts: 1
Joined: Fri Sep 07, 2012 1:28 pm

Interfacing of 6.4" display with raspi

Thu Dec 27, 2012 4:21 pm

I want to interface PD064VT2(6.4" display) with raspberry pi.
How should I proceed and what are the steps
datasheet of PD064VT2:
http://pdf1.alldatasheet.com/datasheet- ... 64VT2.html

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