TTBIT SCRYPT USB Stick Miner User Guide
Last updated on 04/06/2019
Page 16
don’t have a multimeter, you can wing voltages by following the diagrams
below for Pot positions. Use the flat edge of the pot screw as the pointing
direction (DO NOT OVERVOLT at the high end if you don’t have a
multimeter to double check what the voltage is).
The sticks are shipped with the stock voltage settings of the pots (which is
the flat end of the Pot pointing down). The Core voltage is at around .75v,
which is good for up to around 800mhz stable, and ranges from ~.6 ->
~.95v . The memory voltage is set to ~.85v, and ranges from ~.625 -> ~1.05v
(more on memory voltage in tuning section below).
DO NOT go past .9v on the core voltage, you will most likely damage the
ASIC if you run at high voltages and high clocks for prolonged periods of
time.
7a. Tuning
Tuning any switching transistor based processing unit revolves around
supplying enough current so the transistors on the chips actually switch on
and off correctly within their cycle times. The main voltage that will effect
performance and the tuning outlined below is the Core Voltage.
The higher the frequency the less time a transistor has to charge so you
need more current (i.e. turn up the voltage). If these requirements are not
met the transistors don’t function properly and you have what you know as a
“Hardware Error”.
7b. Memory Voltage
I included a Pot for memory voltage mostly for efficiency gains by
undervolting memory. Adjusting memory voltage should be a one time thing,
you set it at the lowest setting it will start hashing. There is no benefit in
increase memory voltage at higher clocks, as this wont increase your hash
rate or bring down hardware errors (this is entirely dependent on core
voltage). Either your device will work at a certain memory voltage or it wont,
so the goal is to bring the voltage down to the lowest possible setting that the
stick will still hash at.
The stock value for memory is supposed to be .9v, but my tests showed all
ASICs operate fine at .85v which is what they ship at. Most ASICs will work
fine down to ~.76 v.
