1.方案参考TIDA-01568，内存布线没有改动。
2.通过TF卡引导，样板一切正常。
UBOOT启动打印如下：
U-Boot 2018.01-svn396 (Mar 27 2019 - 14:19:09 +0800)
CPU : AM335X-GP rev 2.1
Model: TI AM335x EVM
DRAM: 512 MiB
NAND: 0 MiB
MMC: OMAP SD/MMC: 0, OMAP SD/MMC: 1
*** Warning - bad CRC, using default environment
<ethaddr> not set. Validating first E-fuse MAC
Net: cpsw
data abort
pc : [<9ff59188>] lr : [<9ff4cf53>]
reloc pc : [<8081a188>] lr : [<8080df53>]
sp : 9df13228 ip : 9df13180 fp : 00000017
r10: 80860578 r9 : 9df1eed8 r8 : 4030cdcc
r7 : 9ff99c54 r6 : 9ff99bbc r5 : 9ff99c58 r4 : 1f73f000
r3 : 44e3e000 r2 : b0010000 r1 : 9ff99c84 r0 : 00000000
Flags: nZcv IRQs off FIQs on Mode SVC_32
Resetting CPU ...
resetting ...
U-Boot SPL 2018.01-svn396 (Mar 27 2019 - 14:19:09)
Trying to boot from MMC1
*** Warning - bad CRC, using default environment
reading u-boot.img
reading u-boot.img
reading u-boot.img
reading u-boot.img
