ARM2440 识别LTE数据卡问题
Linux已经识别出数据卡对应的端口为 ttyUSB0和ttyUSB1 ，但是发送AT命令无法接收到终端响应（Windows下是正常的）.
另外，通过 cat /dev/ttyUSB0 也无法显示发送和接收的数据. 但是我通过write函数写的数据返回是成功的。
yaffs: Attempting MTD mount on 31.3, "mtdblock3"
yaffs: auto selecting yaffs2
yaffs: restored from checkpoint
yaffs_read_super: isCheckpointed 1
VFS: Mounted root (yaffs filesystem) on device 31:3.
Freeing init memory: 168K
usb 1-1: New USB device found, idVendor=12d1, idProduct=14fe
usb 1-1: New USB device strings: Mfr=2, Product=1, SerialNumber=0
usb 1-1: Product: HUAWEI Mobile
usb 1-1: Manufacturer: HUAWEI
usb 1-1: configuration #1 chosen from 1 choice
option 1-1:1.0: GSM modem (1-port) converter detected
usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
option 1-1:1.1: GSM modem (1-port) converter detected
usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
eth0: link up, 100Mbps, full-duplex, lpa 0xCDE1
请问下，这个是我的write实际并没有写入到终端么？
[解决办法]
这个信息显示是正常的 在贴一些出来
[解决办法]
我用cat /dev/ttyUSB0 跟踪交互一点输出都没；如果用其他终端看，可以看到AT命令交互的。
另外 调用write 返回为成功的。
有其他调试输出手段或者工具么？
try to open com /dev/ttyUSB0
set done!
com return fd=3
cmd_len = 8
open com successfully, now you can input AT command!
AT CMD: AT+
write 4 bytes to com!
read 0 bytes from com: (这里如果先用cat 跟踪，则不会返回）
[解决办法]
Linux version 2.6.32.2-FriendlyARM (root@localhost.localdomain) (gcc version 4.3
.2 (Sourcery G++ Lite 2008q3-72) ) #20 Fri May 11 16:31:10 CST 2012
CPU: ARM920T [41129200] revision 0 (ARMv4T), cr=c0007177
CPU: VIVT data cache, VIVT instruction cache
Machine: FriendlyARM Mini2440 development board
Converting old-style param struct to taglist
ATAG_INITRD is deprecated; please update your bootloader.
Memory policy: ECC disabled, Data cache writeback
On node 0 totalpages: 16384
free_area_init_node: node 0, pgdat c04e727c, node_mem_map c0524000
Normal zone: 128 pages used for memmap
Normal zone: 0 pages reserved
Normal zone: 16256 pages, LIFO batch:3
CPU S3C2440A (id 0x32440001)
S3C24XX Clocks, (c) 2004 Simtec Electronics
S3C244X: core 405.000 MHz, memory 101.250 MHz, peripheral 50.625 MHz
CLOCK: Slow mode (1.500 MHz), fast, MPLL on, UPLL on
Built 1 zonelists in Zone order, mobility grouping on. Total pages: 16256
Kernel command line: noinitrd root=/dev/mtdblock3 init=/linuxrc console=ttySAC0
PID hash table entries: 256 (order: -2, 1024 bytes)
Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
Memory: 64MB = 64MB total
Memory: 59652KB available (4612K code, 441K data, 168K init, 0K highmem)
SLUB: Genslabs=11, HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
Hierarchical RCU implementation.
NR_IRQS:85
irq: clearing subpending status 00000002
timer tcon=00000000, tcnt a4ca, tcfg 00000200,00000000, usec 00001e57
Console: colour dummy device 80x30
console [ttySAC0] enabled
Calibrating delay loop... 201.93 BogoMIPS (lpj=504832)
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
NET: Registered protocol family 16
S3C2440: Initialising architecture
S3C2440: IRQ Support
S3C24XX DMA Driver, (c) 2003-2004,2006 Simtec Electronics
DMA channel 0 at c4808000, irq 33
DMA channel 1 at c4808040, irq 34
DMA channel 2 at c4808080, irq 35
DMA channel 3 at c48080c0, irq 36
S3C244X: Clock Support, DVS off
bio: create slab <bio-0> at 0
SCSI subsystem initialized
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
s3c-i2c s3c2440-i2c: slave address 0x10
s3c-i2c s3c2440-i2c: bus frequency set to 98 KHz
s3c-i2c s3c2440-i2c: i2c-0: S3C I2C adapter
Sangoma WANPIPE Router v1.1 (c) 1995-2000 Sangoma Technologies Inc.
cfg80211: Calling CRDA to update world regulatory domain
NET: Registered protocol family 2
IP route cache hash table entries: 1024 (order: 0, 4096 bytes)
TCP established hash table entries: 2048 (order: 2, 16384 bytes)
TCP bind hash table entries: 2048 (order: 1, 8192 bytes)
[解决办法]
dmesg 其他信息有点错。。被公司防火墙栏了。发不出来..@@