AT91SAM9X35突然断电，在上电偶尔停止Calibrating delay loop... 。重新烧写内核也不可以。启动打印出来的信息：
RomBOOT
Start AT91Bootstrap...
Init DDR... Done!
Downloading image...
chip id: 0xecda
Copy 0x50000 bytes from 0x40000 to 0x26f00000
Done!
U-Boot 2010.06 (Aug 22 2013 - 15:19:27)
DRAM: 128 MiB
NAND: 256 MiB
*** Warning - bad CRC or NAND, using default environment
In: serial
Out: serial
Err: serial
Net: No ethernet found.
Hit any key to stop autoboot: 0
NAND read: device 0 offset 0x200000, size 0x250000
2424832 bytes read: OK
## Booting kernel from Legacy Image at 22000000 ...
Image Name: Linux-2.6.39
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 2392032 Bytes = 2.3 MiB
Load Address: 20008000
Entry Point: 20008000
Verifying Checksum ... OK
Loading Kernel Image ... OK
OK
Starting kernel ...
Uncompressing Linux... done, booting the kernel.
Linux version 2.6.39 (root@qk) (gcc version 4.4.1 (Sourcery G++ Lite 2009q3-67) ) #53 Thu Sep 5 17:49:38 CST 2013
CPU: ARM926EJ-S [41069265] revision 5 (ARMv5TEJ), cr=00053177
CPU: VIVT data cache, VIVT instruction cache
Machine: Atmel AT91SAM9X5-EK
Memory policy: ECC disabled, Data cache writeback
Clocks: CPU 400 MHz, master 133 MHz, main 12.000 MHz
Built 1 zonelists in Zone order, mobility grouping on. Total pages: 32512
Kernel command line: mem=128M console=ttyS0,115200 mtdparts=atmel_nand:8M(bootstrap/uboot/kernel)ro,-(rootfs) root=/dev/mtdblock1 rw rootfstype=ubifs ubi.mtd=1 root=ubi0:rootfs
PID hash table entries: 512 (order: -1, 2048 bytes)
Dentry cache hash table entries: 16384 (order: 4, 65536 bytes)
Inode-cache hash table entries: 8192 (order: 3, 32768 bytes)
Memory: 128MB = 128MB total
Memory: 124916k/124916k available, 6156k reserved, 0K highmem
Virtual kernel memory layout:
vector : 0xffff0000 - 0xffff1000 ( 4 kB)
fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB)
DMA : 0xff000000 - 0xffe00000 ( 14 MB)
vmalloc : 0xc8800000 - 0xfee00000 ( 870 MB)
lowmem : 0xc0000000 - 0xc8000000 ( 128 MB)
modules : 0xbf000000 - 0xc0000000 ( 16 MB)
.init : 0xc0008000 - 0xc002c000 ( 144 kB)
.text : 0xc002c000 - 0xc0497a48 (4527 kB)
.data : 0xc0498000 - 0xc04c8ec0 ( 196 kB)
NR_IRQS:192
AT91: 128 gpio irqs in 4 banks
irq 1: nobody cared (try booting with the "irqpoll" option)
[<c0037300>] (unwind_backtrace+0x0/0xec) from [<c006d454>] (__report_bad_irq+0x30/0x98)
[<c006d454>] (__report_bad_irq+0x30/0x98) from [<c006d650>] (note_interrupt+0x194/0x230)
[<c006d650>] (note_interrupt+0x194/0x230) from [<c006c128>] (handle_irq_event_percpu+0x160/0x18c)
[<c006c128>] (handle_irq_event_percpu+0x160/0x18c) from [<c006c17c>] (handle_irq_event+0x28/0x38)
[<c006c17c>] (handle_irq_event+0x28/0x38) from [<c006e0c0>] (handle_level_irq+0xb8/0xe0)
[<c006e0c0>] (handle_level_irq+0xb8/0xe0) from [<c002c074>] (asm_do_IRQ+0x74/0xa4)
[<c002c074>] (asm_do_IRQ+0x74/0xa4) from [<c0031f54>] (__irq_svc+0x34/0x60)
Exception stack(0xc0499f10 to 0xc0499f58)
9f00: c04a3828 00000000 00000000 20000053
9f20: c0498000 00000002 00000000 c049dfd4 0000000a 41069265 200254bc 00000000
9f40: 00000000 c0499f58 c002c084 c0047310 20000053 ffffffff
[<c0031f54>] (__irq_svc+0x34/0x60) from [<c0047310>] (__do_softirq+0x40/0x108)
[<c0047310>] (__do_softirq+0x40/0x108) from [<c002c084>] (asm_do_IRQ+0x84/0xa4)
[<c002c084>] (asm_do_IRQ+0x84/0xa4) from [<c0031f54>] (__irq_svc+0x34/0x60)
Exception stack(0xc0499f90 to 0xc0499fd8)
9f80: 00008001 c04a35f8 00000000 20000053
9fa0: c04c8f00 c0026ebc c0026eb8 c049dfd4 20000000 41069265 200254bc 00000000
9fc0: 00000000 c0499fd8 c00631b0 c0008810 20000053 ffffffff
[<c0031f54>] (__irq_svc+0x34/0x60) from [<c0008810>] (start_kernel+0x1a0/0x2cc)
[<c0008810>] (start_kernel+0x1a0/0x2cc) from [<20008038>] (0x20008038)
handlers:
[<c003c77c>] (at91sam926x_pit_interrupt+0x0/0xa0)
Disabling IRQ #1
Console: colour dummy device 80x30
console [ttyS0] enabled
Calibrating delay loop...
原本运行得好好的，突然就启动不了了。问题估计不在软件。这几天经常出现，我照找出了一个解决方法（并不是本质的解决方法），把核心板拔下来插上去就OK 了。因此怀疑是硬件问题。具体原因没有找到。