Now I always unplug the AC adapter and remove the battery before powering up my flasher (although I do leave the chip-clip connected).
This is about right. I programmed most of INTEL platforms using dediprog SF100: ATOM: from D4xx/D5xx (Pine Creek) series, TNC, BYT-M/I, BSW and CORE (IVB, HSW, BDX-DE, BDW-H, SKL-Y/U), whereas for some HSW-U series it was necessary to put platform in S5 state by shutting down them to S5. AC in most cases removed, I did not have battery since I played with test platforms. And there were 4x2 pins connectors for most of platforms, recently with special small connector forms and adapters for SF100 programming heads, but in some cases I needed clip to connect directly to flash.
Zoran
On Thu, Dec 1, 2016 at 3:02 PM, Trammell Hudson hudson@trmm.net wrote:
On Thu, Dec 01, 2016 at 01:15:59PM +0000, Peter Stuge wrote:
Michael Carbone wrote:
I have been attempting to use a raspberry pi for spi flashing and when
I
use the 3.3v pin the raspberry pi doesn't power up as the chip draws
too
much power through the 3.3v pin for the raspberry pi to also run.
It's not the flash chip drawing current, it's the rest of the mainboard.
For some mainboards (like the 15" 2014 Macbook Pro) I had to add a 1-10 Ohm resistor on the power lead from my flasher, which basically glitches the rest of the mainboard, but since many SPI flash chips can run at a slightly lower voltage it allowed me to read/write the firmware. This is probably not the right way to do it.
[...]
Looking online [1] some folks recommend using laptop AC adapter + wake-on-lan (and not using the VCC/3.3v pin), but I'm not sure that's a dependable strategy
In fact I consider it the *only* dependable strategy. It is the obvious way to adhere to the required power up sequence.
I've never had success with this technique due to the multi-master situation that you described. The PCH (or ME?) on modern CPUs seemed to always be driving the IO lines when I provided power. Now I always unplug the AC adapter and remove the battery before powering up my flasher (although I do leave the chip-clip connected).
Perhaps I'm a little more YOLO with many of my test machines than is prudent, so I don't worry too much about what other bits are being powered up by the 3.3V rail. On the x230 I used an external bench supply and found that the rail needed about 110 mA to function:
https://www.flickr.com/photos/osr/28494632165/lightbox
So on my teensy 2 flasher I replaced the small SMD regulator with a larger UA78M33 regulator in a TO-220 package that can supply 500mA:
https://www.flickr.com/photos/osr/30531707094/lightbox
My biggest problem these days is that the chipclips seem to wear out after a few hundred applications (the pins get pushed upwards, making the connection flaky). Anyone have a recommendation for one that can stand up to constant use?
-- Trammell
-- coreboot mailing list: coreboot@coreboot.org https://www.coreboot.org/mailman/listinfo/coreboot