Pandora Hardware Debug Support On Pandora


Erku

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Apr 27, 2008
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Hi,

I've searched the forum without finding much information about this (sorry if I missed something).

1. Cortex-A8 has EMT (optional?), will the dev boards have a trace port? and if so what are the spec,
port width, etc?

2. Will it be posssible to modify the production Pandora to get access to JTAG ports or other debug features?
 
JTAG port is accessible through pads on the PCB. Trace port is not accessible as it requires extra buffering and consideration to prevent signal stubs and transmission line problems. Pandora is a great development platform for OMAP, but it is still a consumer product first.
 
Hey Laurent, I'm glad to see you here. Bienvenu! (if I correctly deduced you are the SFML creator :D)
 
Ok. ETM would have been nice but I will be quite happy with jtag.

Laurent > I cant imagine anything more fun than ETM. But thats just me ;-)
 
Erku said:
Laurent > I cant imagine anything more fun than ETM. But thats just me ;-)

My "kidding" comment was not about the fun factor of ETM. It's that, as Michael wrote, the Pandora is a consumer product first and so adding HW just for the benefit of some individuals is not a good thing :)
 
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Gammenon said:
Hey Laurent, I'm glad to see you here. Bienvenu! (if I correctly deduced you are the SFML creator :D)
You were not completely wrong, I was around there ;)

(Sorry to spoil the thread)
 
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So it ought to be possible to use a standard USB debugger (such as the OpenOCD one through OLIMEX) to debug the Pandora board?

I have a feeling this is probably the case, but better be safe and ask... (I have very little experience with ARM atm)
 
Vladimir said:
So it ought to be possible to use a standard USB debugger (such as the OpenOCD one through OLIMEX) to debug the Pandora board?

I have a feeling this is probably the case, but better be safe and ask... (I have very little experience with ARM atm)
I don't think OpenOCD supports Cortex-A8 at the moment.
 
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Vladimir said:
So it ought to be possible to use a standard USB debugger (such as the OpenOCD one through OLIMEX) to debug the Pandora board?
If it supports the Cortex-A8 and the required voltages, yes. However, I don't think OpenOCD does.
 
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Squidge said:
Vladimir said:
So it ought to be possible to use a standard USB debugger (such as the OpenOCD one through OLIMEX) to debug the Pandora board?
If it supports the Cortex-A8 and the required voltages, yes. However, I don't think OpenOCD does.

Any (budget) suggestions to that one, then?
 
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Vladimir said:
Any (budget) suggestions to that one, then?

With bugdet in mind, you can forget the idea at the moment of a finished product.
Why do you need JTAG debug? Unless you are doing low level kernel development it's not really needed I guess.
 
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Laurent said:
Vladimir said:
Any (budget) suggestions to that one, then?

With bugdet in mind, you can forget the idea at the moment of a finished product.
Why do you need JTAG debug? Unless you are doing low level kernel development it's not really needed I guess.

So true, I'm going to try to play it safe by getting the retail version rather than a dev kit.

You're spot on with the JTAG thing. I'm still looking around for any decent ARM emulators (ideally something like the Bochs for ARM development), but a hardware debugger is probably my best bet. Now, is there an ARM wiki for these things, or does somebody need to make one? :rolleyes:

The prices I've seen for some debuggers (£195 for an IAR JTAG one for ARM/Cortex, £695 with ETM?!?) And the h/w emulators, well... Someone's supposed to be doing their degree over here :p

Perhaps some of the developers could comment on (affordable) debuggers they've used in the past? Thanks for your help guys.
 
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Vladimir said:
You're spot on with the JTAG thing. I'm still looking around for any decent ARM emulators (ideally something like the Bochs for ARM development), but a hardware debugger is probably my best bet. Now, is there an ARM wiki for these things, or does somebody need to make one? :rolleyes:

ARM forbids the writing of software emulator for its ARMv7 cores. The only exception is qemu.
However qemu does not yet have support for OMAP3.

As far as hardware emulators are concerned, I don't use them even for kernel hacking as I am one of the few having access to v7 simulators, which I find more convenient that HW debug ;)
 
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Vladimir said:
Perhaps some of the developers could comment on (affordable) debuggers they've used in the past? Thanks for your help guys.
The only hardware debuggers I've used on ARM Cortex is the XDS560 and the IAR/Segger J-Link.

I wrote my own debugger for ARM7-10 using a hacked up Keil U-Link which had the nice functionality of being able to update the firmware of the dongle via the USB port (It used a Cypress EZ-USB chip, to which I just happened to have a Dev kit for :))
 
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Seems like the IAR/Segger J-Link is cheaper when bundled with NXP's boards! :eek:

One more question - how many pins is the J-Tag pad thing on the Pandora board?
 
Vladimir said:
Seems like the IAR/Segger J-Link is cheaper when bundled with NXP's boards! :eek:
No, it's a cut down version. The full price JTAG will run at higher speeds than the ones bundled with other peoples boards. It's still perfectly adequate however and it still runs at several Mhz. If I remember correctly, the "proper" J-Link run at 8Mhz, whilst the bundled ones run at 2mhz.

I know the place where I work buys development boards with bundled jlink's, and then gives/throws away the dev boards as it's a lot cheaper and the speed doesn't matter that much.

Vladimir said:
One more question - how many pins is the J-Tag pad thing on the Pandora board?
I would suspect 14, the TI standard.
 
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