Boot Sources

The GPIO is used to select the boot vector and BootLoader source and offer multiple methods to obtain the BootLoader image.

The JH7100 SoC can boot from one of the sources listed in the following table, as selected by the PAD_GPIO [62:60] values.

Table 1. PAD_GPIO Values for Boot Source Selection
Processor SCFG_boot_mode PAD_GPIO [63] Boot Vector PAD_GPIO [62:60]
U74 0x1 - SCFG_u74_reset_vector -
0x0 (default) 0x0 0x00_2000_0000, XIP Flash

0x0: 1-bit quad SPI NOR flash memory

0x1: 4-bit quad SPI NOR flash memory

0x2: SDIO (Reserved)

0x3: eMMC (Reserved)

0x4: UART

0x5: USB (Reserved)

0x6: chiplink (Reserved)

0x7: SPI2AHB (Reserved)
0x1 0x00_1840_0000, on-chip BootROM (32KB)
Note:
  • The boot mode and boot source selection (PAD_GPIO [63]) can be read through syscon status registers.
  • Use the GPIO pad to select the vector and loader source by default.
  • PAD_GPIO [63] and PAD_GPIO [62:60] can be configured to 1 or 0 via pull-up/pull-down resister, button or jumper according to board hardware design.
Figure 1. Hardware Boot Sequence