Data Sheet

Thundercomm TurboX C40x SOM Datasheet
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2.3.14. Boot configuration interface
Configure fuses or BOOT_CONFIG pins.
 BOOT_CONFIG pins provide flexibility during product development.
 Fuses should be blown for production devices.
 BOOT_CONFIG [3:1] is MSB-aligned with Fast_Boot [2:0].
Table 2-20. Boot Configurations
BOOT_CONFIG[3:1] Boot Options Notes
0b000 Try SDC1 --> SDC2 --> USB2.0 Default
0b001 Try SDC2 --> SDC1
0b010 Try SDC1
0b011 Try USB2.0
Default boot configuration (0b000) is eMMC on SDC1.
Special boot-related GPIO features:
 They are sensed for boot-purposes during IC reset (during fuse sense).
 After boot up, use them for normal GPIO functions.
 Do not have pull-ups on GPIO_55, GPIO_56, GPIO_57, and GPIO_49 prior to blowing FAST_BOOT fuses.
The boot configuration function of the preceding GPIOs is sampled at the rising edge of RESOUT_N reassertion.
Table 2-21. Boot Configuration GPIO definition
Boot Configuration Interface
Pin Name PIN Location Voltage Type Description Notes
GPIO_45 114 P3 IO Forced USB boot; Configurable I/O
GPIO_55 B26 P3 IO
Fast boot select bit 0 (configure external boot device);
WDOG_DISABLE. Configurable I/O
GPIO_56 A27 P3 IO Boot select bit 1 (configure external boot device); Configurable I/O
GPIO_57 B27 P3 IO Boot select bit 2 (configure external boot device); Configurable I/O
GPIO_49 118 P3 IO Boot select bit 3 (configure external boot device); Configurable I/O
Forced USB boot
During development or factory production, boot from USB_HS port are forced by using GPIO_45.
 FORCED_USB_BOOT (GPIO_45) always takes precedence, regardless of the state of the BOOT_CONFIG
 FORCED_USB_BOOT is checked first during the boot device detection prior to BOOT_CONFIG GPIOs.
 GPIO_45 = 1 forces the SDM device to boot from USB_HS port.
Blow the FORCE_USB_BOOT_DISABLE fuse to disable the feature that forces USB boot using GPIO_45.
nicholas.wang_thundercomm.com
2022-07-21 2:34:47 AM CST