TE0820 POR with JTAG TE0790

[pema]

Hi there,
Question: How to POR the TE820 after flashing it, without physical interaction?
Problem Description: Every time after flashing the TE820 eMMC I need to perform a POR over the RESIN signal line (Connector JM2 Pin 18). This can be either over the push button on the Carrier board or with a full power reset.

I have tried already all kinds of reset over the XSCT but none of them seems to work. So I normally, just have one of those cheap wifi  power plugs connected to the TE820 to perform a POR( by power OFF power ON).

Is there any other way to perform this without needing to press the Push button or Power boot? Perhaps a signal line from the TE0790 to perform the POR ? ( I could solder a wire to the Carrier board) XMOD E and XMOD G are still free. Would it be possible to provide the code to the CPLD in the TE0790 or modify it in order to provide a SRST signal over XSCT?

Many Thanks  and have a nice weekend .

[JH]

Hi,
CPLD Code is available on the download area, here is a link to update instructions and download:
https://wiki.trenz-electronic.de/display/PD/TE0790+CPLD+Firmware

Links to other TE0790 documentation an downloads:
https://wiki.trenz-electronic.de/display/PD/TE0790+Resources

If you get access from TE0790 programmer to the module depends on the carrier.
Which carrier did you use?
TE0706?
br
John

[pema]

Hi John,
many thanks for your reply. Yes I have a TE706 carrier. 
I will have to solder a wire RST to J2 pin G in the JTAG adapter.
The signal from connector J2 pin G already gives this signal right ?. How is the signal activated from the xsct/xsdb?

Many thanks
Have a nice weekend.

[JH]

Hi,

The signal from connector J2 pin G already gives this signal right ?. How is the signal activated from the xsct/xsdb?

that's not possible or much effort. xsct/sdb use JTAG for communication. JTAG is only one channel from FTDI(translate USB to JTAG) which is routed through the CPLD. CPLD is only Levelshifter with the advance that you can change Pinout from the 2,54mm pinheader if needed.

I can't tell you what AMD transmits and how, only AMD knows that.
Instead of HW Reset U+ Zynq has mechanism to reboot via JTAG, I think that's what AMD try when they say reboot.
But there are different depths of reboot possible, not all of them reset all registers and re-evaluate the boot mode again, so this does not always work

You can check if you find some mechanism from TRM:
https://docs.xilinx.com/r/en-US/ug1085-zynq-ultrascale-trm
And U+ Zynq register description:
https://docs.xilinx.com/r/en-US/ug1087-zynq-ultrascale-registers

or you create you custom carrier with microcontroller, which can force reset.

br
John

[pema]

Hi John,
yes I realize that you cant know what AMD over the xsct/xsdb sends.
Can you please tell me what is the purpose from the  "Button (Reset_n)" on the JTAG TE0790 2x6 Pin Header ? Input? output?
Thanks.

[JH]

Hi,
Button goes directly to the 2.54 mm pinheader(so output from XMOD):
https://wiki.trenz-electronic.de/display/PD/TE0790+TRM#TE0790TRM-BlockDiagram
and to this pin(Input for CPLD). It simple xor LED so you can see that you press the button
https://wiki.trenz-electronic.de/display/PD/TE0790+CPLD+-+XMOD+Standard#TE0790CPLDXMODStandard-LED

Or see schematics and source code.

In case you didn't press button, than you can also use G as output or set G as tri state with pullup activated where you force only to GND, in this case you didn't get a electrical conflict when someone press the button.


br
John

[pema]

Ok I got it. now. Thanks for clearing that up.