Nothing from DBGU port

[Brian Williamson]

I've had my SAM9G45 for a while now and so far no joy.  I do not have a screen attached nor do I want one - hopefully this doesn't pose any problems.

So far I've managed to write the console version of angstrom to 2 different micro sd cards multiple times.  There is clearly a difference upon power up - without the micro I get nothing but a solid LED.  With the sd card I get a little noise from the speaker and a second LED light for about half a second.  

That brings me to the debug port.  There is no data coming from it.  I don't have a serial to TTL converter yet - it's on order.  I've cobbled together a temporary solution using capacitors and a MAX232.  This seems to be working up to the SAM because at every step in the wiring I can conduct a loopback test and get a good result.  Swapping the wires on SAM doesn't help.

I have the serial port on the computer set to 115200 baud 8N1.

Any suggestion would be greatly appreciated.

[Daniel Palmer]

>With the sd card I get a little noise from the speaker and a second LED light for about half a second.  

That's a good sign I think. I remember the speaker making a crunch sound when some part of the hardware is initialised.

>cobbled together a temporary solution using capacitors and a MAX232. 

Which side of the MAX232 is connected to the SAM? It should be the 3.3v logic side. 

>Any suggestion would be greatly appreciated.

Hook it up to your network and use nmap or your DHCP server's client table to find it and ssh into it.

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[Brian Williamson]

Which side of the MAX232 is connected to the SAM? It should be the 3.3v logic side. 

I'm starting to think this is my problem but I have to admit I'm still to new to know for sure.  I'm using pins 11 and 12 of the MAX232 chip with a 5v Vcc.  I suspect that I should be using the 3.3v version of the Max232.  Ring any bells? 

[Brian Williamson]

Hook it up to your network and use nmap or your DHCP server's client table to find it and ssh into it.

I tried this some time ago.  I got the lights on the ethernet port actively blinking however I could not find the address in the DHCP client list. 

[Daniel Palmer]

I haven't used a max232 in ages but I think its just a case that logic one on the TTL side is VCC. You might have fed 5v logic into the SAM UART and popped it. I haven't checked the datasheet  but I'm pretty sure it's up to 3.6v like most 3.3v stuff. Get a cp2102 USB to serial board and try with that.

On 24 Apr 2013 20:34, "Brian Williamson" <bwill...@nysus.net> wrote:

Which side of the MAX232 is connected to the SAM? It should be the 3.3v logic side. 

I'm starting to think this is my problem but I have to admit I'm still to new to know for sure.  I'm using pins 11 and 12 of the MAX232 chip with a 5v Vcc.  I suspect that I should be using the 3.3v version of the Max232.  Ring any bells? 

--

[Brian Williamson]

On Wednesday, April 24, 2013 8:30:20 AM UTC-4, Daniel wrote:

I haven't used a max232 in ages but I think its just a case that logic one on the TTL side is VCC. You might have fed 5v logic into the SAM UART and popped it. I haven't checked the datasheet  but I'm pretty sure it's up to 3.6v like most 3.3v stuff. Get a cp2102 USB to serial board and try with that.

I think that's going to be my plan.  I have a TTL to serial adapter coming in and it handles 3.3v as well at 5v so I should be good there.

In some of the research I conducted this morning there was mention of the MAX232 being 5v and the MAX3232 being 3.3v.  I suspect that's the problem.  So I should be receiving my converter any day now so it's just a matter of patience.

Thanks!