Quote from: elasticband on February 21, 2014, 11:58:06 PM

Quote from: bondus on February 16, 2014, 01:17:19 PM

I have inspected what the November firmware has actually changed.

What I can see it has changed a value in one of the registers in the VRMs. It has set the "ON" bit in the OPERATIONS register,changing what conditions are needed to turn the VRMs on.
This change will be permanent even if rebooted or power-cycled. It can be changed using i2c commands:

Turn all VRMs on:

#!/bin/sh
# Stop SPI poller
i2cset -y 2 0x71 2 0

for b in 3 4 5 6 7 8 ; do
   for d in 0 1 2 3 4 5 6 7 ; do
   i2cset -y $b 0x1$d 1 0x80 >/dev/null 2>&1
   done
done

Restore to factory settings:

#!/bin/sh
# Stop SPI poller
i2cset -y 2 0x71 2 0

for b in 3 4 5 6 7 8 ; do
   for d in 0 1 2 3 4 5 6 7 ; do
   i2cset -y $b 0x1$d 1 0x0 >/dev/null 2>&1
   done
done

I suggest stopping cgminer before doing this to limit the power when the operation is done.

Reading the datasheet for the VRMs I can see that when using them in pairs (as we do when all are turned on) there are some requirements on how they should be turned on. This method does not do that!

I have heard that hizzing sound as well. Some boards do that. They did that on 0.90 firmware too. No idea why.

I do not know if this is safe or not, it might be unsafe and burn your boards.

I was not referring to this particular script/functionality, i.e. enabling all VRMs.

Bondus said that 1.00 do not apply voltage settings to all the VRMs even if they are all enabled, this is bad because the VRMs are supposed to work in couple by desing. Having different voltage settings on coupled VRMs could demage the HW.