you-wouldnt-reverse-engineer-a-rat / g305-re

Reverse engineering of the G305 mouse by Logitech
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hero-sensor input-device input-device-re logitech-mouse reverse-engineered

g305-re

g305

Reverse engineering of the G305 mouse by Logitech

Specs

Spec Range Unit
DPI 200 - 12000 -
Max acceleration 40 g
Max Tracking speed 400 I/s
Report Rate 1 kHz
Processor Core 32-bit ARM -
Claimed Battery Life 250 hours

Eletrical Characteristics

Characteristic Range Unit
Active Power 10 mW
Idle Power * 4 mW
Sleep Power ** 200 uW
Deep Sleep Power *** ?
Turn On Voltage **** 1.35 V
Max Voltage ***** 2.0 (3.6?) V
     * No movement
    ** After approximately 90 seconds idle
   *** After ~10 minutes of sleep? (to be measured)
  **** Below this voltage the device is consistently unable to start
 ***** The device can tolerate more (tested up to 5.5V),
but above 4.8V it seems to consume unusually high power during Deep Sleep,
and above 2.0V the main voltage bus (nominal 2.0V) follows the input voltage (the same appens with the led 3.7V bus) meaning it goes over
the normal opperating conditions, still unkown if it has any long term impact (cryomods is currently running a long term test on one), suspission is that it is generally safe.

These are rough conservative approximations (though measured with fairly good equipment). Measurements on a single personal device.

Radio

Frequency range: 2.402-2.481 GHz Modulation Technology: GFSK

PCB as populated a Ceramic chip Antenna capable of 2.4 to 2.4835GHz.

FCC Documents for the mouse.

Expected Battery Life

Battery Weight [g] Nominal Voltage [V] Capacity [mAh] Capacity [mWh] Active Battery Life [h]
ALkaline LR6 (AA) 1.5 1800 – 2850 2700 - 4275 270 - 428
ALkaline LR03 (AAA) 1.5 860 – 1200 1290 - 1800 129 - 180
Lithium 14500 (AA) 3.6 600 - 840 (1600 @ 1.5V) 2160 - 3024 (2400 @ 1.5V) 216 - 302
Lithium 10440 (AAA) 3.6 350 1260 126
PR675 1.85 1.4 550 - 600 770 - 840 77 - 84
Super Capacitor 70F 18 2.7 - - 5.83
Super Capacitor 30F 6.9 - 9.7 2.7 - - 2.5

source: AAA Battery, source: AA Battery

Receiver

g305-receiver

FCC Documents

Frequencies: 2.402 to 2.481GHz

Modulations technology: GFSK

Antenna Type: Printed

MCU: TI CC2544

Reverse engineering of the receiver is not planned

hardware

The hardware was traced in gimp, and can be analyzed in there too (everything is layered), file is here. Whatch out, the top is mirrored!

g305-re-bot g305-re-top g305-re-overlay

Mechanical

CAD drawings of the G305 available in cad

g305_pcb credit to inornate on thingiverse.

Components

The main board consists of:

testpoints

The PCB contains the following testpoints:

testpoint Funcion Additional Info
TP1 VIN + Direct from battery 1.5V
TP2 VIN - Direct from battery
TP3 Does not Exist?
TP4 Does not Exist?
TP5 Does not Exist?
TP6 P0.04 Unused Pin Breakout
TP7 Does not Exist?
TP8 Does not Exist?
TP9 Does not Exist?
TP10 GND
TP11 VDD
TP12 SWDIO
TP13 SWCLK
TP14 RESET
TP15 P0.22 SWO?
TP16 P0.08 Unused Pin Breakout
TP17 P0.09 Unused Pin Breakout
TP18 P0.10 Unused Pin Breakout
TP19 P0.29 Unused Pin Breakout
TP20 P0.30 Unused Pin Breakout
TP21 P0.31 Unused Pin Breakout
TP22 P0.27 Unused Pin Breakout
TP23 P0.28 Unused Pin Breakout

MCU

The MCU is a nRF52810 from nordicsemi, ARM Cortex M4 Package: QFN-48 Endianness of the MCU: Little Endian

Pin name Function
P0.11 CS
P0.12 MOSI
P0.13 MISO
P0.14 SCLK
~ ~
P0.15 LMB
P0.16 RMB
P0.17 MMB
P0.18 forward side button
P0.19 back side button
P0.20 dpi button
~ ~
P0.23 encoder pull up resistors (power saving)
P0.00 wheel encoder
P0.01 wheel encoder
~ ~
P0.02 battery analog input
P0.03 3.7V (RGB VDD) enable
~ ~
P0.05 red LED
P0.06 green LED
P0.07 blue LED

firmware

Initially plans were made to break APPPROTECT and dump the firmware, but it appears logitech never enabled it (you ok? lol)

firmware dumps

Sensor

The G305 comes with a HERO sensor, made in house by logitech, based on the mercury.

A reverse engineering effort towards this sensor will be made in a separate repo hero-re.