be4r
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dim ACT light

Thu May 22, 2014 2:39 pm

I scoured the internet and forums for a solution and this is the only question I have. I just received my second raspberry pi because I thought the first was defective, and the second still gets the faint light. So it must be the contents of the SD card.

I downloaded noobs and put all the contents on the root of my SD Card. I plug everything into the Raspberry Pi carefully and a solid red light comes on with a very dim green light. I found this online:

Check that you have correctly written a Raspberry Pi image to the card by using a MAC or PC and browse for the following files:
bootcode.bin
fixup.dat
start.elf amongst others

I only see bootcode.bin in the noobs files. I cannot find fixup.dat or start.elf. I downloaded noobs off the site many times but still cannot find these files. Please help?

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mahjongg
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Re: dim ACT light

Thu May 22, 2014 3:03 pm

start by reading the relevant sticky:
http://www.raspberrypi.org/forums/viewt ... 28&t=58151

be4r
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Re: dim ACT light

Thu May 22, 2014 3:37 pm

i read the sticky. I have formatted the SD card numerous times and downloaded the NOOBS v1.3 numerous times. Made sure the extracted files are in the root folder. Supposedly the new version of NOOBS does not require fixup.dat or start.elf? I tried pressing 1 and 2 on my keyboard but still there is no bright green light. I am using a Transcend 8GB SDHC card which is marked as compatible on the list of cards. My power is outputting at least 5.1v. I made sure the connectors touch on the sd card reader.

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mahjongg
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Re: dim ACT light

Sat May 24, 2014 1:42 pm

be4r wrote:i read the sticky. I have formatted the SD card numerous times and downloaded the NOOBS v1.3 numerous times. Made sure the extracted files are in the root folder. Supposedly the new version of NOOBS does not require fixup.dat or start.elf? I tried pressing 1 and 2 on my keyboard but still there is no bright green light. I am using a Transcend 8GB SDHC card which is marked as compatible on the list of cards. My power is outputting at least 5.1v. I made sure the connectors touch on the sd card reader.
the green light should start blinking the moment the PI is able to boot code from the card, when it cannot read any boot files then it stays as it is (with barely visible light, due to the unprogrammed nature if the GPIO it hangs off from, which per default has a very weak pull-up). It makes no sense pushing any keys if that doesn't happen, as no code has ever ran! The first thing the boot code does is to program the LED's GPIO, still weak LED light means no code has ever ran!


did you really measure the voltage the PI receives? outputting 5.1V and 5.1V arriving on the board are not the same thing. Also you may think you have written the card correctly, but that not a guarantee that you really did. And the card might be on the list, but that doesn't matter if your card is a fake one!

don't you know anyone else with a PI that can help you, if only by lending his card and power supply, or testing your card on his PI?

hampi
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Re: dim ACT light

Sun May 25, 2014 4:09 pm

I have a similar problem with my RPiA now. It was working for about one month, but now no boot any more. I have three different 8GB SD cards: Transcend 4, Transcend 10 and Lexar 6. They have the Rasbian Wheezy from January 2014 and the Wheezy from September 2013 on the Transcend 4. All of these cards boot in my RPiB while in RPiA only Transcend 4 boots and Transcend 10 and Lexar 6 do not boot. I tried also putting the September 2013 Wheezy on the Lexar 6 and it boots on RPiB but not on RPiA.

For me this looks like a software bug somewhere in the SoC firmware when the SD card is initially read at boot time. That could explain also why the same model SD card is sometimes reported to work and other times to fail in elinux.org . Or if somebody has a better explanation I am interested to hear that too.

suicidal_orange
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Re: dim ACT light

Sun May 25, 2014 4:34 pm

@hampi if the card isn't properly connected the same thing happens, try booting with your finger on the back of the card and see if that helps.

If it does check that your socket isn't breaking - mine is :(

hampi
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Re: dim ACT light

Sun May 25, 2014 6:45 pm

suicidal_orange wrote:@hampi if the card isn't properly connected the same thing happens, try booting with your finger on the back of the card and see if that helps.
Thanks for the reply. I tried that already a few times. Checked also the SD card dimensions with a calliper. I can not spot any mechanical problem in my cards.

Next thing would be to measure the signals and voltages going to the SD card. I was reading the wiki documentation on that.

hampi
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Re: dim ACT light

Sun May 25, 2014 8:44 pm

Some interesting results. If I connect the logic analyser (Saleae 20 MHz model) to the SD card slot soledered pins 3 (GND), 5 (SCLK) and 7 (MISO) the boot does happen in my RPiA with 8GB Transcend 10 card. Then after removal of the logic analyser wires no boot anymore.

I have no idea if my simple logic analyser is capable to read the data between the SoC and SD card, but it shows atleast that some traffic is going on the pins 1 (SPI _CS), 2 (MOSI), 5 (SCLK) and 7 (MISO).

The pin numbering is from the SD card wiki. I do not know if the protocol is really SPI or something else, but as far as I understand from the wiki only SPI is free from license fees.

hampi
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Re: dim ACT light

Tue May 27, 2014 8:43 pm

I was experimenting more the boot problem tonight. My "fix" seems to be to solder a 3 cm long insulated wire both to pin 5 (SCLK) and pin 7 (DATA0). These wires are then twisted together. The RPiA seems to boot with these wires, but without them no boot. The reason behind all this might be a subtle EMC issue related to the design of the printed circuit board. I will leave the "fix" in place and see what happens.

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