紧急求助OMAPL138的UART0无法发送数据的原因

用示波器测试UART0的管脚，无波形。UART0和MII复用，故将MII的PINMUX屏蔽，而使用PINMUX3设置，经内核启动信息，查看UART0中断配置正常，并通过ehco "test">/dev/ttyS0,然后输入cat /proc/tty/driver/serial,发现TX发送数据增加，但无法测试到管脚有波形。内核启动信息如下：
               MUX: initialized UART0_RXD
MUX: Setting register UART0_RXD
           PINMUX3 (0x0000000c) = 0x00000000 -> 0x00020000
MUX: initialized UART0_TXD
MUX: Setting register UART0_TXD
           PINMUX3 (0x0000000c) = 0x00020000 -> 0x00220000
bio: create slab at 0
SCSI subsystem initialized
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
cfg80211: Calling CRDA to update world regulatory domain
Switching to clocksource timer0_1
musb_hdrc: version 6.0, cppi4.1-dma, host, debug=0
Waiting for USB PHY clock good...
musb_hdrc: USB Host mode controller at fee00000 using DMA, IRQ 58
musb_hdrc musb_hdrc: MUSB HDRC host driver
musb_hdrc musb_hdrc: new USB bus registered, assigned bus number 1
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 1 port detected
NET: Registered protocol family 2
IP route cache hash table entries: 1024 (order: 0, 4096 bytes)
TCP established hash table entries: 1024 (order: 1, 8192 bytes)
TCP bind hash table entries: 1024 (order: 0, 4096 bytes)
TCP: Hash tables configured (established 1024 bind 1024)
TCP reno registered
UDP hash table entries: 256 (order: 0, 4096 bytes)
UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
NET: Registered protocol family 1
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
################################################
EMAC: RMII PHY configured.
################################################
JFFS2 version 2.2. (NAND) © 2001-2006 Red Hat, Inc.
msgmni has been set to 54
alg: No test for stdrng (krng)
io scheduler noop registered (default)
da8xx_lcdc da8xx_lcdc.0: GLCD: Found G05VN01 panel
Console: switching to colour frame buffer device 60x34
Serial: 8250/16550 driver, 3 ports, IRQ sharing disabled
serial8250.0: ttyS0 at MMIO 0x1c42000 (irq = 25) is a 16550A
serial8250.0: ttyS1 at MMIO 0x1d0c000 (irq = 53) is a 16550A
console [ttyS1] enabled
serial8250.0: ttyS2 at MMIO 0x1d0d000 (irq = 61) is a 16550A
NAND device: Manufacturer ID: 0xec, Chip ID: 0xdc (Samsung NAND 512MiB 3,3V 8-bit)
Bad block table not found for chip 0
Bad block table not found for chip 0
Scanning device for bad blocks
Bad eraseblock 1920 at 0x00000f000000
Creating 5 MTD partitions on "davinci_nand.1":
0x000000000000-0x000000020000 : "u-boot env"
0x000000020000-0x000000040000 : "UBL"
0x000000040000-0x0000000c0000 : "u-boot"
0x000000200000-0x000000600000 : "kernel"
0x000000600000-0x000020000000 : "filesystem"
davinci_nand davinci_nand.1: controller rev. 2.5
setup mode 0,  8 bits/w, 3000000 Hz max --> 0
davinci SPI Controller driver at 0xfef0e000 (irq = 56) use_dma=1
dm9000 Ethernet Driver, V1.31
eth0: dm9000a at c2808e00,c280ce10 IRQ 134 MAC: 00:61:6e:64:79:31 (platform data)
usbcore: registered new interface driver asix
usbcore: registered new interface driver cdc_ether
usbcore: registered new interface driver net1080
usbcore: registered new interface driver rndis_host
usbcore: registered new interface driver cdc_subset
usbcore: registered new interface driver zaurus
usbcore: registered new interface driver rndis_wlan
usbcore: registered new interface driver rt2800usb
console [netcon0] enabled
netconsole: network logging started
ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
ohci ohci.0: DA8xx OHCI
ohci ohci.0: new USB bus registered, assigned bus number 2
ohci ohci.0: irq 59, io mem 0x01e25000
hub 2-0:1.0: USB hub found
hub 2-0:1.0: 1 port detected
usbcore: registered new interface driver wusb-cbaf
usbcore: registered new interface driver cdc_wdm
Initializing USB Mass Storage driver...
usbcore: registered new interface driver usb-storage
USB Mass Storage support registered.
mice: PS/2 mouse device common for all mice
input: gpio-keys as /devices/platform/gpio-keys/input/input0
setup mode 0,  8 bits/w, 3000000 Hz max --> 0
ads7846 spi1.6: touchscreen, irq 130
input: ADS7846 Touchscreen as /devices/platform/spi_davinci.1/spi1.6/input/input1
omap_rtc omap_rtc: rtc core: registered omap_rtc as rtc0
omap_rtc: RTC power up reset detected
omap_rtc: already running
watchdog watchdog: heartbeat 60 sec
cpuidle: using governor ladder
cpuidle: using governor menu
TCP cubic registered
NET: Registered protocol family 17
lib80211: common routines for IEEE802.11 drivers
Clocks: disable unused emac
Clocks: disable unused mcasp
Clocks: disable unused mmcsd
Clocks: disable unused spi0
davinci_emac_probe: using random MAC addr: 6e:77:0a:a7:ee:11
emac-mii: probed
omap_rtc omap_rtc: setting system clock to 2000-01-01 00:31:59 UTC (946686719)
yaffs: dev is 32505860 name is "mtdblock4" rw
yaffs: passed flags ""
VFS: Mounted root (yaffs2 filesystem) on device 31:4.
Freeing init memory: 432K

[ 本帖最后由 r16721853 于 2011-9-27 15:42 编辑 ]