BeagleboardxM Rev C sys_boot pin configuration.

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1

I am learning board bring-up on beagleboard - xM Rev C.

As per the Datasheet of DM3730 processor, Chapter-26 [Initialization], section[26.2.3]Boot Configuration, there are seven pins namely sys_boot[6:0] present in processor [AH26, AG2 6, AE14, AF18, AF19, AE21, AF21][sys_boot0 to sys_boot[6]]. Out of seven pins, sys_boot[6] is used for oscillator setting, so sysboot[5:0] are used for booting configuration, it means different values of pins[0 or 1, pullup/pulldown] will decide different settings for booting options like UART/USB/MMC1-2/NOR/NAND etc…

Now,As per schematics of BBxM Rev-C pin connections are confusing me whether they are 1 or 0, because they are pulled up and pulled down as well. These pins are multiplexed and adding the more confusion. Please help me to find the correct combination of values of pins to find which boot config my board is having and processor’s ROMCode is using to boot the system from.

Thanks!!!

2

Look at the resistors. If they say DNI, they are not installed. This is the way options are implemented for future use if needed.

Gerald

3

Reply in 2 minutes Awsome.Thanks a lot Gerald.Here is the final summary of pin configuration:

PULLUPS:
SYS_BOOT0=AH26=DNI
SYS_BOOT1=AG26=10K
SYS_BOOT2=AE14=DNI
SYS_BOOT3=AF18=DNI
SYS_BOOT4=AF19=10K
SYS_BOOT5=AE21=NOPULLUP
SYS_BOOT6=AF21=10K
PULLDOWN:
SYS_BOOT0=AH26=10K
SYS_BOOT1=AG26=DNI
SYS_BOOT2=AE14=10K
SYS_BOOT3=AF18=10K
SYS_BOOT4=AF19=DNI
SYS_BOOT5=AE21=10K
SYS_BOOT6=AF21=DNI

FINAL CONNECTIONS:
SYS_BOOT0=AH26=PULLDOWN= 0
SYS_BOOT1=AG26=PULLUP= 1
SYS_BOOT2=AE14=PULLDOWN= 0
SYS_BOOT3=AF18=PULLDOWN= 0
SYS_BOOT4=AF19=PULLUP= 1
SYS_BOOT5=AE21=PULLDOWN= 0
SYS_BOOT6=AF21=PULLUP= 1

SYS_BOOT6=1 ==> Clock source is from PowerIC.[page3546 DM3730 TRM].
SYS_BOOT5=0 ==> Memory Preffered Booting Order.[page 3549 DM3730 TRM]
SYS_BOOT[4:0][10010] ==> FirstBoot=MMC1
SecondBoot=USB
ThirdBoot=UART3

Thanks .
Israr

4

This is all described in the System Reference Manual.

Gerald