The nRF21540 DK has a range of solder bridges for enabling or disabling functionality on the Development Kit (DK). Changes to these are not needed for normal use of the DK.
The following table is an overview of the solder bridges on the nRF21540 DK.
| Solder bridge | Default | Function |
|---|---|---|
| SB5 | Closed | Cut to disconnect LED1 |
| SB6 | Closed | Cut to disconnect LED2 |
| SB7 | Closed | Cut to disconnect LED3 |
| SB8 | Closed | Cut to disconnect LED4 |
| SB9 | Open | Short to bypass peripheral power switch |
| SB30 | Open | Short to reset the interface MCU |
| SB31 | Open | Short to bypass the USB detect switch |
| SB32 | Open | Short to permanently enable the I2C pull-up resistors |
| SB33 | Closed | Cut to permanently disable the I2C pull-up resistors |
| SB34 | Open | Short to bypass the power switch on the USB power |
| SB36 | Open | Short to bypass the power switch on the external supply power |
| SB37 | Open | Short to bypass the interface MCU power switch |
| SB38 | Closed | Cut to disable VDD power to the Arduino interface |
| SB39 | Open | Short to bypass the power switch for regulator or external supply |
| SB40 | Closed | Cut for current measurements of the VDD_nRF |
| SB41 | Closed | Cut for current measurements of the VDD_nRF_HV |
| SB42 | Closed | Cut to disconnect Reset button from nRF52840 reset pin when the interface MCU is disconnected |
| SB43 | Open | Short to connect Reset button to RESET pin on the Arduino interface |
| SB44 | Open | Short to connect the RESET pin on the Arduino interface to the nRF52840 reset pin |
| SB45 | Open | Short to connect the RESET pin on the Arduino interface to the interface nRF52840 reset pin when the interface MCU is disconnected |
| SB46 | Open | Short to connect the RESET pin on the Arduino interface to the interface MCU Boot when the interface MCU is disconnected |
| SB47 | Open | Short to enable power supply of the external device when using the debug out connector |
| SB48 | Open | Short to bypass the interface MCU USB power switch |
| SB49 | Open | Short to connect VDD_UTMI to VDD_SAM |
| SB50 | Closed | Cut to disconnect the nRF52840 CTS line from the signal switch and interface MCU |
| SB51 | Closed | Cut to disconnect the nRF52840 RTS line from the signal switch and interface MCU |
| SB52 | Closed | Cut to disconnect the nRF52840 RxD line from the signal switch and the interface MCU |
| SB53 | Closed | Cut to disconnect the nRF52840 TxD line from the signal switch and interface MCU |
| SB54 | Closed | Cut to disconnect the nRF52840 SWDIO line from the signal switch and interface MCU |
| SB55 | Closed | Cut to disconnect the nRF52840 SWDCLK line from the signal switch and interface MCU |
| SB56 | Closed | Cut to disconnect the nRF52840 RESET line from the signal switch and interface MCU |
| SB57 | Closed | Cut to disconnect the nRF52840 SWO line from the signal switch and the interface MCU |
| SB58 | Closed | Cut to disconnect voltage follower from external supply when SW10 is in ON position |
| SB59 | Open | Solder to connect debug in and trace reference voltage to VDD |
| SB60 | Closed | Cut to disconnect debug in and trace reference voltage from VDD_nRF' |
| SB65 | Closed | Cut to disable the pull-up resistor of the IMCU_BOOT line |
| SB80 | Open | Short to bypass the power switch for the VBUS of nRF52840 |
| SB81 | Open | Short to bypass the power switch for VDD_HV of nRF52840 |