Config Button & Settings¶
The KXUSBC2 has a small push button that can be accessed using a paper clip etc. through the side panel.
Button press functions¶
| Press | Duration | Action |
|---|---|---|
| Short | < 1 second | Attempt a PD role swap — useful for charging from devices that can also act as a power source (e.g., recent iPhones) |
| Medium | 1–3 seconds | Enter the config menu — only works when nothing is connected to the KXUSBC2 (LED is off) |
| Long | > 3 seconds | System reset — restarts the KXUSBC2 |
Navigating the config menu¶
When you enter the config menu, the LED blinks yellow at 1-second intervals. The number of blinks indicates which menu item you're currently viewing.
- Short press — advance to the next menu item
- Medium press — enter the currently selected menu item (LED blinks blue to show the current setting)
- Short press changes the setting
- Medium press exits the menu item
- Long press — exit the menu and restart with new settings
Menu items¶
| # | Menu item | Available values (blink counts) |
|---|---|---|
| 1 | Charging current limit | 500 mA (1), 1000 mA (2), 2000 mA (3 ), 3000 mA (4) |
| 2 | DC input current limit | 500 mA (1), 1000 mA (2), 2000 mA (3), 3000 mA (4 ) |
| 3 | Charge while rig is on | Disable (1 ), Enable (2) |
| 4 | Thermistor | Disable (1 ), Enable (2) |
= default setting
Walkthrough: enable charging while the rig is on
- Press the button for 1–3 seconds (LED blinks yellow, indicating menu item 1)
- Press the button briefly two times to reach menu item 3 (LED will blink 3 times before cycling)
- Press the button for 1–3 seconds to enter menu item 3 (LED blinks blue once, indicating that the setting is currently disabled)
- Press the button briefly to toggle to "enable" (two blinks)
- Press the button for 1–3 seconds to exit the menu item
- Press the button for > 3 seconds to restart
Configuration options¶
Advanced settings can be configured via EEPROM, using the web-based programmer — no software installation required (just a simple serial UPDI programming adapter).
| Setting | Range | Default |
|---|---|---|
| Role | SRC, SNK, DRP, TRY_SRC, TRY_SNK | DRP |
| PD mode | Off, PD 2.0, PD 3.0 | PD 3.0 |
| Charging current limit | 50–5000 mA | 2000 mA |
| Charging voltage limit | 10000–18800 mV | 12600 mV (3S Li-Ion) |
| DC input current limit | 100–3300 mA | 3000 mA |
| OTG current limit | 120–3320 mA | 3000 mA |
| Discharging voltage limit | minimum battery voltage for OTG | 9000 mV |
| OTG voltage headroom | 0–500 mV | 100 mV |
| Allow charging while rig is on | boolean | false |
| Enable thermistor | boolean | false |
| User RTC offset | -127 to +127 ppm | 0 |
4S LiFePO₄ batteries
Adjust the charging voltage limit to approximately 14.2 V — stay below the BMS cutoff to avoid over-voltage faults.