Hello Dennis,
It looks like the memory location you ask about (400h) is first cleared by line
40 of LegacyBda.c:
ZeroMem (Bda, 0x100);
Then it is set to 3F8h by line 1945 of LegacyBootSupport.c:
Bda->Com1 = SioPtr->Serial[0].Address;
Maybe some breakpoints or debug prints in that area will lead to the solution.
Thanks,
Scott
From: lowell_den...@dell.com [mailto:lowell_den...@dell.com]
Sent: Thursday, August 21, 2014 11:20 AM
To: edk2-devel@lists.sourceforge.net
Subject: Re: [edk2] How to use serial port (COM1) in EFI shell
Dell - Internal Use - Confidential
I ran the suggested command
dh -p SerialIo
and got Protocol ID 'SerialIo' could not be identified.
However running
dh -p SerialIO
competed without error but dumped nothing to the screen.
</Lowell>
From: Li, Elvin [mailto:elvin...@intel.com]
Sent: Tuesday, August 19, 2014 8:29 PM
To: edk2-devel@lists.sourceforge.net <mailto:edk2-devel@lists.sourceforge.net>
Subject: Re: [edk2] How to use serial port (COM1) in EFI shell
You may check if SerialIo protocol is generated on your platform. Serial driver
is loaded but may be not started.
You could run dh -p SerialIo in shell to check.
From: lowell_den...@dell.com <mailto:lowell_den...@dell.com>
[mailto:lowell_den...@dell.com]
Sent: Wednesday, August 20, 2014 5:48 AM
To: edk2-devel@lists.sourceforge.net <mailto:edk2-devel@lists.sourceforge.net>
Subject: [edk2] How to use serial port (COM1) in EFI shell
All,
I have a system with a serial port on it over which I would like to send some
information.
This is a real serial port, not a USB to serial module.
The serial port works perfectly as COM1 in Windows7
When boot my USB key to FreeDOS it does not work right away.
If I use debug to write 0xF8 and 0x03 to 40:0 and 40:1 respectively then the
serial port works perfectly as COM1.
When I boot my USB key to the EFI shell (v2.0) I can see the serial driver is
loaded when I execute the "drivers" command, but the
"sermode" command says "no serial ports found".
Can anyone please help me to get serial communications working in the EFI shell.
Thanks,
Lowell Dennis
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