Serial Communications Ports



Santiago Allen
07-09-2005, 10:24 PM
Hi All,

Im getting some strange results with my Communications ports, and Id
like to see if anyone has encountered anything similar. Here are the
details:

Total 8 Communication Ports should be availiable
4 On - Motherboard Ports
4 On - Custom board ports

Using Device manager in my xpe image I have the following results.


IF I enable all the comports in BIOS and set the standard addresses
COM1 IRQ 4 3F8
COM2 IRQ 3 2F8
COM3 IRQ 11 3E8
COM4 IRQ 10 2E8

Device Manager Reports :
Communications Port (COM1)
Communications Port (COM1)
Communications Port (COM2)
Communications Port (COM2)
SERIAL CHANNEL (COM3)
SERIAL CHANNEL (COM4)
SERIAL CHANNEL (COM5)
SERIAL CHANNEL (COM6)


Notice that there are 2 COM1 and 2 COM2. These 4 onboard ports
obviously do not work in this state. Im not sure why the ports are
being resolved to the same name, especially if they are on different
IRQ and Hex Addresses.

IF I change the Bios settings to:

COM1 Auto
COM2 Auto
COM3 IRQ 11 3E8
COM4 IRQ 10 2E8

I Get:

Communications Port (COM1)
Communications Port (COM2)
SERIAL CHANNEL (COM3)
SERIAL CHANNEL (COM4)
SERIAL CHANNEL (COM5)
SERIAL CHANNEL (COM6)

Bios COM1 and COM2 are present at 3f8 and 2f8 but the third and fourth
onboard serial ports are no longer detected.

I dont know if this is necessarily a windows problem, a bios problem or
an NTDETECT problem, but I do know my setupapi log will show 4 ports
when using the first method and 2 ports when using the second, but it
doesnt show what the ports were going to be named.

Anyone see something similar?

Thanks,

Santiago

Santiago Allen
07-09-2005, 10:24 PM
New Information:

In XP Pro, the same configuration that XPE will report as:

Communications Port (COM1)
Communications Port (COM1)
Communications Port (COM2)
Communications Port (COM2)
SERIAL CHANNEL (COM3)
SERIAL CHANNEL (COM4)
SERIAL CHANNEL (COM5)
SERIAL CHANNEL (COM6)

Is:
Communications Port (COM1)
Communications Port (COM1)
Communications Port (COM2)
Communications Port (COM4)
SERIAL CHANNEL (COM3)
SERIAL CHANNEL (COM4)
SERIAL CHANNEL (COM5)
SERIAL CHANNEL (COM6)

Com1 is repeated twice and thats it.....Im guessing this is a BIOS
problem or Ntdetect problem?

Any know issues with the MB870 P4 Mini ITX Board?

Thanks,

Santiago Allen


Serial Communications Ports