Originally Posted by tryest
JTAG pinouts are a IEEE 1149 standard. you want to use it for flash programming or CPU emulation?
Sorry I was an ass earlier in the thread.
I am looking for flash programming, console output, and disaster recovery.
To clarify my question. I'm trying to figure out which of the hundred or so pads available on the Rezound are the jtag pads. Actually I'd be happy with any uart.
disclaimer: I am new to all this and learning as I go along.
This is the location of what I think is most likely what I am looking for so far:
I didn't realize the pads were there hiding behind the ribbon cable when I was taking the pictures and then when I was testing them later I forgot to get a fresh pic with the ribbon removed. They basically look like:
but on the opposite side of the phone.
If they are ARM-20 jtag pinouts then here are the pad names and measured voltages (question marks till I know for sure what they are):
1. vref? | 1.8/1.27/0
2. nTRST? | 0.0
3. TDI? | 1.63/.87/1.15/0
4. TMS? | 1.63/.87/1.15/0
5. TCK? | 1.63/.87/1.15/0
6. TRCK? | 0.04/0
7. TDO? | 0.04/0
8. NSRST? | 1.71/0
9. DBGRQ? | 0.0
10. DGBACK? | 0.0
I kept my multimeter on each tab for about a minute each. If there is more than one listed it is because they were cycling. I'm sure there are other intermediate states, but I have a very slow multimeter )=
For reference's sake here are a couple definitions:
- vRef Reference voltage – used to condition voltage level of Vsupply.
- nTRST JTAG TAP Reset
- TDI JTAG Test Data Input line
- TMS JTAG Test Data Output line
- TCK JTAG Test Clock, controls communication independently from the system clock.
- TDO JTAG Test Data Output line
- RTCK Returned Test Clock – used for adaptive clocking (supported on CTM and USB2/JTAG. *Note that not all ARM based MCUs implement this signal.
- nSRST Target System Reset
- DBGRQ Debug request.
- DBGACK Debug acknowledge
I'll be interfacing what ever I come up with using an Arduino. My primary desire is to get console output so I can debug hboot and kernel during boot. The kernel's default console is ttyHSL3. In addition to this UART 3 is available for debugging. I'll be happy with what ever I can get working. There should also be an SPI interface, and a program called ser2net (hosts serial console to network). I haven't been able to get ser2net working though.