Bureaucrats, dave_user, Administrators
4,650
edits
Changes
no edit summary
[1] Nevertheless, SBC Lynx can support this option. This is a clear example of a feature that can be implemented on request. For more information please contact [mailto:sales@dave.eu|Sales department].
===Internal boot===
When ''Internal boot'' mode is selected, ''GPIO override'' technique is used to configure bootstrap flags, also known as <code>BOOT_CFG</code> bits. This means that 24 processor's signals - specifically LCD1_DATA[23:00] - need to be pulled up or down to select the proper configuration. The following table summarizes these configurations. Pull-up/down resistors are 10kOhm.{|class="wikitable" style="text-align: center;"|-!Ordering code(s)!LCD_DATA23 (BOOT_CFG4_7)!LCD_DATA22 (BOOT_CFG4_6)!LCD_DATA21 (BOOT_CFG4_5)!LCD_DATA20 (BOOT_CFG4_4)!LCD_DATA19 (BOOT_CFG4_3)!LCD_DATA18 (BOOT_CFG4_2)!LCD_DATA17 (BOOT_CFG4_1)!LCD_DATA16 (BOOT_CFG4_0)!LCD_DATA15 (BOOT_CFG2_7)!LCD_DATA14 (BOOT_CFG2_6)!LCD_DATA13 (BOOT_CFG2_5)!LCD_DATA12 (BOOT_CFG2_4)!LCD_DATA11 (BOOT_CFG2_3)!LCD_DATA10 (BOOT_CFG2_2)!LCD_DATA09 (BOOT_CFG2_1)!LCD_DATA08 (BOOT_CFG2_0)!LCD_DATA07 (BOOT_CFG1_7)!LCD_DATA06 (BOOT_CFG1_6)!LCD_DATA05 (BOOT_CFG1_5)!LCD_DATA04 (BOOT_CFG1_4)!LCD_DATA03 (BOOT_CFG1_3)!LCD_DATA02 (BOOT_CFG1_2)!LCD_DATA01 (BOOT_CFG1_1)!LCD_DATA00 (BOOT_CFG1_0)!Notes|-| XUBx0xxx<br>XUBx2xxx|| pull-down || pull-down || pull-down || pull-down || pull-up || pull-down || pull-down || pull-down || pull-up || pull-up || pull-up || pull-up || pull-up || pull-up || pull-down || pull-up || pull-up || pull-down || pull-down || pull-up || pull-up || pull-up || pull-up || pull-up || pull-up |||-| XUBx1xxx<br>XUBx2xxx|| || || || || || || || || || || || || || || || || || || || || || || || || |||}
selection of the device from which the Boot ROM retrieves Program Image along with several further device-specific configuration settings, can be done in two different ways, depending on <code>BT_FUSE_SEL</code> bit:
* 0 (shipped value): GPIOs
**This technique - also known as ''GPIO override'' - is typically used during the development stage. It allows to use 24 GPIOs (specifically LCD1_DATA[23:00]) to configure <code>BOOT_CFG</code> bits.
* 1: eFUSE.
**In this case <code>BOOT_CFG</code> bits are fetched from OTP memory.
