应用背景
我们的产品是GPS产品，GPS模块是通过TX与RX来和CPU串口控制器的UART2连接的，对应于COM3(这个可以根据自己的项目的需要来定)，platform.reg中注册表信息如下：
;==========GPS===== UART2===COM3===============
[HKEY_LOCAL_MACHINE/Drivers/BuiltIn/Serial2]
"DeviceArrayIndex"=dword:2
"Irq"=dword:f
"MemBase"=dword:50008000
"MemLen"=dword:30 ;; 2c
"InterruptBitsShift"=dword:6 ; UART 2 Interrupt Sub Register shift bit.
;"ISTTimeouts"=dword:200 ; every 512 ticks checking Modem status.
"Prefix"="COM"
"Index"=dword:3
"Dll"="serial_smdk2443.Dll"
"Order"=dword:0
"Priority"=dword:0
"Port"="COM3:"
"DeviceType"=dword:0 ; IRDA modem, 0 -> null modem
"FriendlyName"="GPS COM3"
"IClass"="{CC5195AC-BA49-48a0-BE17-DF6D1B0173DD}"
"DevConfig"=hex: 10,00, 00,00, 05,00,00,00, 10,01,00,00, 00,4B,00,00, 00,00, 08, 00, 00, 00,00,00,00
应用程序通过COM2可以接受到GPS发送的数据并进行解析，把解析出来的数据在shell上显示，给用于直观的GPS数据。应用端往往需要多个COM口来接受GPS发送的数据，那么如何解决这个问题了，可以通过基于COM3来虚拟多个串口出来，这样可以打开多个COM口来接受GP发送过来的数据，如何实现呢？只需要做一下动作就可以实现了。
1. 使用vspd.dll来实现虚拟多个串口功能，这个驱动在网上应该很容易找到的。
2. 如果是WINCE5.0那么就在platform.bib中加入：
vspd.dll $(_FLATRELEASEDIR)/vspd.dll NK SH
如果是WINCE6.0系统，那么就在platform.bib中加入：
vspd.dll $(_FLATRELEASEDIR)/vspd.dll NK SHK
对于WINCE5.0和WINCE6.0系统，这个vspd.dll驱动是通用的。
3.在platform.reg中加入
[HKEY_LOCAL_MACHINE/Drivers/BuiltIn/VSPD0]
"Priority"=dword:00000000
"DeviceArrayIndex"=dword:00000000
"PortIsRO"=dword:00000000
"SplitPort"=dword:00000003
"Index"=dword:00000001
"Prefix"="COM"
"Dll"="vspd.dll"
"DeviceType"=dword:00000000
"Tsp"="Unimodem.dll"
"FriendlyName"="Virtual port COM1"
"DevConfig"=hex:10,00,00,00,05,00,00,00,10,01,00,00,00,4b,00,00,00,00,08,00,00,00,00,00,00
[HKEY_LOCAL_MACHINE/Drivers/BuiltIn/VSPD1]
"Priority"=dword:00000000
"DeviceArrayIndex"=dword:00000001
"PortIsRO"=dword:00000000
"SplitPort"=dword:00000003
"Index"=dword:00000005
"Prefix"="COM"
"Dll"="vspd.dll"
"DeviceType"=dword:00000000
"Tsp"="Unimodem.dll"
"FriendlyName"="Virtual port COM5"
"DevConfig"=hex:10,00,00,00,05,00,00,00,10,01,00,00,00,4b,00,00,00,00,08,00,00,00,00,00,00
[HKEY_LOCAL_MACHINE/Drivers/BuiltIn/VSPD2]
"Priority"=dword:00000000
"DeviceArrayIndex"=dword:00000002
"PortIsRO"=dword:00000000
"SplitPort"=dword:00000003
"Index"=dword:00000006
"Prefix"="COM"
"Dll"="vspd.dll"
"DeviceType"=dword:00000000
"Tsp"="Unimodem.dll"
"FriendlyName"="Virtual port COM6"
"DevConfig"=hex:10,00,00,00,05,00,00,00,10,01,00,00,00,4b,00,00,00,00,08,00,00,00,00,00,00
上面的注册表就是基于COM3，虚拟出COM1、COM5和COM6，这样这4个COM口都可以用于和GPS通信了，在这里强调一点，就是注册表项"SplitPort"=dword:00000003的值一定要和实际的COM口一致(在此是COM3)。