November 25, 2024

Antminer S9 board - Reset button

As shipped, these boards do not have a working reset button. However, I have discovered that it is very easy to configure one.

It helps if you have, like I do, a hot air rework station. If you have a very fine pitch soldering iron and good skills, you should be able to manage this.

The board has two buttons, labeled S1 and S2 on the silkscreeen (and on the schematic). We can reconfigure S1 to be a reset.

The S1 button is next to the red/green LED. If you look behind it you will see R23, R22, and R24 marked on the silkscreen. R24 is missing. The game is to move R23 to R24. Get busy and just do it.

Explanation

R22 (in the middle) is a 4.7K pull up to the V2.5 power rail. The button is normally open and closes to ground when pushed. R23 and R24 are zero ohm "shunts" - it they were just jumpers this would be even easier.

With the "resistor" on R23, the switch is connected to MIO-47 and they label it as "key-reset". This could be monitored by software or generate an interrupt (more likely).

With the "resistor" moved to R24, the switch is connected to PS_SRST#, which is an active low reset to the PS (the ARM processors). The signal also goes to the LSF0102DCTR chip, which will generate a JTAG reset.

It works and is a nice thing to have available.

Feedback? Questions? Drop me a line!

Tom's Computer Info / tom@mmto.org