I was following the upgrade post http://wiki.netduino...duino-Mini.ashx and I've erased the mini with 5V to the gold pad. Now I can't get SAM-BA 2.12 to see the mini.
Using this pinout reference http://wiki.netduino...nout-Cards.ashx
I'm Using a USB BUB II - both power and logic set to 5V
RX to pin 1
TX to pin 2
5V to 21
GND to 23
Com3 is the USB Serial port: 115200, 8, n, 1
All I get when trying to connect is "communication error". Same effect when I swap Rx/Tx lines.
Have I accidentally killed my Mini - how can I check and avoid wasting more time?
Dead Mini
Started by Jack Chidley, Oct 04 2012 03:39 PM
6 replies to this topic
#2
Chris Walker
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Posted 04 October 2012 - 04:11 PM
Hi Jack,
The SAM7X chips have fairly tight timing requirements during their initialization. We've found that Keyspan USB to RS232 adapters work great, but have had mixed success with other solutions.
It's most likely that your Netduino Mini is okay, and that SAM-BA is just having a really hard time connecting to the Netduino Mini.
BTW, be sure to connect the GND from both the power supply _and_ your RS232 adapter to the Netduino Mini. If only one is connected, then you won't be able to communicate reliably.
Chris
#3
Jack Chidley
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Posted 04 October 2012 - 04:38 PM
Connected up a separate, regulated, 5V power supply. Connected both Grounds together. Same result. The Keyspan thing is twice the price of the Netduino Mini so I don't want to go that route.
I have a Netduino Plus, could I connect RS232 through that route (some kind of pass through)?
#4
Chris Walker
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Posted 04 October 2012 - 04:47 PM
Hi Jack,
Unfortunately, the only option to program the Netduino Mini's bootloader is to use a physical RS232 connection or a USB-RS232 adapter which SAM-BA can work with. We've had good luck with most that we've tried, but I know there are a few that don't agree well with SAM-BA.
BTW, is the USB-BUB an RS232 adapter or a TTL serial adapter? If its logic is set to 5V, it's most likely a TTL serial adapter...which won't work on the RS232 pins.
You should be able to pick up the Keyspan adapter for <$30 at Amazon. I know that's a bit pricey.
Chris
#5
Jack Chidley
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Posted 04 October 2012 - 07:58 PM
If I have understood this correctly, the difference between TTL and RS232 is the voltage levels.
TTL
Logic 0 is 0V
Logic 1 is 3.3 or 5v
RS232
Logic 0 is -3V to -15VL
Logic 1 is +3 to +15V
So I need something that outputs RS232 signals. Either
1) USB to RS232 direct
2) TTL to RS232
I saw this one: http://www.ebay.co.u...=item3378b657c0 based on the MAX2323CSE chip.
#6
Jack Chidley
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Posted 06 October 2012 - 08:48 PM
Still can't get it to work. So I am buying the Keyspan. I'll let you know if it works.
Keyspan works.
Edited by Jack Chidley, 11 October 2012 - 10:18 AM.
#7
carb
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Posted 06 October 2012 - 09:42 PM
Jack,Still can't get it to work. So I am buying the Keyspan. I'll let you know if it works.
Managed to update my Netduino Mini today using a Synapse Netduino Mini Breakout board that I got from Jameco.
I had a few problems, but finally got it to work.
The board connects via USB, but must be selected to RS232.
It showed up as Com3, ended up using Sam-Ba 2.11 due to communication error that I got with 2.12 (may have had the board selected to TTL at the time, not sure). I could have tried a higher voltage supply to the breakout but it did update at 5 vdc from the USB.
Tested the board okay after I figured out that Pin 17 was PWM0.
Good luck,
Chuck
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