Flash loader troubles

infoinfo962 · ‎2010-08-10

Posted on August 10, 2010 at 22:14

cschumann · ‎2011-05-17

Posted on May 17, 2011 at 14:01

Hi,

Some months ago I tried the cmd bootloader which did not work for me, too. The error message was the same you had. The GUI bootloader worked both with the Eval board and my own PCB.

When you tried the GUI bootloader did you pull the RST and BOOT pins of the processor in the right order?

Carsten

chikos332 · ‎2011-05-17

Posted on May 17, 2011 at 14:01

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Hi,

I had an exactly similar issue in the past, it was due to the RS232 Gnd which was not correctly connected to PC Gnd. I simply added a wire between RS232 Cable shield (from PC) and the board DB9 connector shield (or Gnd, the same) and I found it was solving the issue. So I just re-soldered the connector correctly.

For your case, when using the probe, you connect the Gnd of the USART to the PC or Oscillo Gnd and the voltages are stabilized.

infoinfo962 · ‎2011-05-17

Posted on May 17, 2011 at 14:01

@Carsten

BOOT0, BOOT1 and reset pins are all stable and at the level they should be (measured to be sure). Otherwise programming would fail even with the probe's ground connected.

@chikos

That's I thought as well, so I measured all connections, cables and shields. No anomalies there. Also measured if there was a voltage difference between the USB connector shield on my laptop and ground of the PSU; 0mV.

But here's also good news. In a rare flash of brilliance I noticed the laptop was hooked up to wallsocket A while the PSU (and scope) was connected to wallsocket B which is on the other side of the room. So I figured it might be worth a try to connect both to the same wallsocket. And voila problem solved it seems. Being a software engineer this solution is beyond my understanding of electrics, so I can't explain any further (but would love to know). But it did the trick.

alexalex9 · ‎2011-05-17

Posted on May 17, 2011 at 14:01

Maybe Ground Loop... think of a loop antenna in a path from socket A to the electrical service, to socket B, connected by your serial cable.. that can induce currents into your serial cable ground. Strange though, 'cause I thought most laps were isolated from the safety ground.