# RB5 DIP switches
Source: [https://docs.qualcomm.com/doc/80-88500-5/topic/RB5-DIP-switches.html](https://docs.qualcomm.com/doc/80-88500-5/topic/RB5-DIP-switches.html)
The RB5 mainboard provides two DIP switches: DIP\_SW\_0 and DIP\_SW\_1.
Figure : RB5 mainboard DIP switches
Table : Board configuration DIP switches
| DIP\_SW\_0 | Name | Details | Default |
| :---: | :---: | :---: | :---: |
| 1 | Mic switch | ON: on board DMIC
OFF: off board DMIC | OFF |
| 2 | Debug UART | ON: debug UART
OFF: off board UART | ON |
| 3 | CBL\_PWR\_N | ON: auto-power-up
OFF: push the power button to power up | OFF |
| 4 | HDMI switch | ON: DSIO to HS1 connector
OFF: DSIO to HDMI bridge | ON |
| 5 | Sensor IMU toggle | ON: SPI to LS3 connector
OFF: SPI to onboard IMU | ON |
| 6 | IMU external clock | ON: external clock to IMU
OFF: internal clock to IMU | OFF |
| DIP\_SW\_1 | Name | Details | Default |
| --- | --- | --- | --- |
| 1 | BOOT\_CONFIG\_1 [GPIO\_27] | Selects external boot devices (see [Table : External boot device selection for RB5 platform](https://docs.qualcomm.com/doc/80-88500-5/topic/RB5-DIP-switches.html#concept.dita_22995754-838b-42a0-8e7b-26af74d081ce__table_9)) | OFF |
| 2 | BOOT\_CONFIG\_2 [GPIO\_47] | Selects external boot devices (see [Table : External boot device selection for RB5 platform](https://docs.qualcomm.com/doc/80-88500-5/topic/RB5-DIP-switches.html#concept.dita_22995754-838b-42a0-8e7b-26af74d081ce__table_9)) | OFF |
| 3 | BOOT\_CONFIG\_3 [GPIO\_76] | Selects external boot devices (see [Table : External boot device selection for RB5 platform](https://docs.qualcomm.com/doc/80-88500-5/topic/RB5-DIP-switches.html#concept.dita_22995754-838b-42a0-8e7b-26af74d081ce__table_9)) | OFF |
| 4 | BOOT\_CONFIG\_0 [GPIO\_128] | ON – disables watchdog
OFF – enables watchdog | OFF |
| | | | |
| | | | |
The following table indicates the external boot device selection for the RB5 platform
based on the DIP\_SW\_1 (1, 2, and 3):
| | GPIO number | GPIO number | GPIO number | GPIO number | |
| --- | --- | --- | --- | --- | --- |
| FAST\_BOOT GPIO bit (3:0) | 90 | 76 | 47 | 27 | Order of boot device selection |
| 0000 | 0 | 0 | 0 | 0 | Default: UFS0 → SDC2 → USB0 → EDL (USB0) |
| 0001 | 0 | 0 | 0 | 1 | SDC2 → USB0 → EDL (USB0) |
| 0010 | 0 | 0 | 1 | 0 | SDC2 → EDL (USB0) |
| 0011 | 0 | 0 | 1 | 1 | USB0 → EDL (SDC2 → USB0) |
| 0100 | 0 | 1 | 0 | 0 | QSPI → EDL (SDC2 → USB0) |
| 0101 | 0 | 1 | 0 | 1 | SPI → EDL (SDC2 → USB0) |
| 0110 | 0 | 1 | 1 | 0 | UFS0 → USB0 → EDL (USB0) |
| 0111 | 0 | 1 | 1 | 1 | Same as fastboot (3:0) = 0000
UFS0 → SDC2 → USB0 → EDL (USB0) |
Terms used in the table:
- UFS: Universal Flash storage
- SDC: Secure disk card
- USB0: USB storage device
- EDL: Emergency Download (EDL) mode or Qualcomm Download (QDL) mode
For example, FAST\_BOOT\_GPIO bit (3:0) → 0000; indicates selection of the external boot
devices for the RB5 platform in the following order: UFS0 → SDC2 → USB0 → EDL (USB0). The
following is the priority: first UFS0, second SDC2, third USB0. If no external devices are
detected, the device falls back to the EDL mode. When power is applied, FORCE\_USB\_BOOT
(GPIO\_132) is checked first, regardless of the state of the BOOT\_CONFIG GPIOs or FAST\_BOOT\_SEL
fuses.
Note: If the board is not powering up, check the setting on DIP switch 3 for the
intended behavior. If the DIP\_SW\_0 switch 3 is OFF, the boards will not automatically power
up unless USB Type-C is plugged in. To automatically boot up, set the DIP\_SW\_0 switch 3 to
ON.
**Parent Topic:** [RB5 mainboard](https://docs.qualcomm.com/doc/80-88500-5/topic/rb5_mainboard.html)
Last Published: Nov 25, 2025
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