Filename: PNPMOUSE.TXT
WWW URL: http://www.firmware.com/support/bios/pnpmouse.htm
FTP URL: ftp://ftp.firmware.com/text/pnpmouse.txt
Revision: 06/17/96 TLS Micro Firmware Technical Support
Summary: Explanation and solution for problem of frozen mouse in
WIN95 after upgrading to PnP BIOS M4HS45/M4HS45G/M4HS45GP.
On the JX30/JX30G motherboard, if a mouse is on COM1 and a non-PnP internal modem is on COM2, the mouse may freeze in WIN95 after upgrading to PnP BIOS (M4HS45/G/GP) and detecting new hardware.
Explanation:
This motherboard uses the National Semiconductor 87311/87312 Peripheral Controller chip to handle the onboard COM ports and LPT port. This chip has 2 physical lines to handle the IRQs for the COM ports. One line is used by COM1 and COM3 and the other line is used by COM2 and COM4. If the onboard COM ports are set to COM1 and COM3 or COM2 and COM4, then both COM ports will be generating an IRQ on the same line which may cause one or both serial devices not to work.
Normally Gateway 2000 installs internal modems on COM1 and puts the mouse on COM2. The other onboard COM port is usually set to DISABLED or sometimes to COM3/IRQ9. However if the modem was purchased later it may have been installed on COM2 and the mouse may be on COM1.
When a PnP BIOS is installed, the onboard ports become PnP nodes, which means that they can then be configured by a PnP operating system, such as Windows 95. After installing the PnP BIOS, it is necessary to detect new hardware in WIN95 in order for WIN95 to recognize the PnP BIOS. After doing this, WIN95 will detect that there are 2 COM ports on the motherboard even if one COM port is disabled. WIN95 will then attempt to enable the disabled COM port and configure it so that it does not conflict with anything else. If a modem is found on COM2/IRQ3 and an oboard COM port (with mouse) is set to COM1/IRQ4, WIN95 will enable the other onboard COM port and set it to COM3/IRQ5. Theoretically this should not cause any problems. WIN95 is not really doing anything wrong and neither is the BIOS. The problem is caused by the fact that WIN95 has no way to be aware of the limitation in the design of the motherboard which causes the onboard COM ports (COM1 and COM3) to share the same wire for their IRQs.
Solution:
The solution is to tell WIN95 to leave the second onboard COM port alone. This is done by going in to the device manager and unchecking the box for Original Configuration under COM3. Since the mouse is not working at this point, it is necessary to use the keyboard to navigate through WIN95. Here are the steps to follow:
At WIN95 Desktop, press TAB until an icon on the Desktop is highlighted.
When an Icon is highlighted, use arrow keys to highlight My Computer.
Press ALT-ENTER on My Computer to get to System Properties.
Press RIGHT ARROW once to highlight Device Manager tab.
Press TAB twice to highlight Computer at top of list.
Arrow down to Ports, press PLUS to open branch, arrow down to COM3.
Press ALT-R on COM 3 to get to Communications Port (COM 3) Properties.
Press SPACEBAR to uncheck box by Original Configuration.
Press TAB once to highlight OK button, then press ENTER.
Press TAB five times to highlight CLOSE, then press ENTER.
Press CTL-ESC to bring up the start menu, press U for shutdown, then press R and then ENTER to restart system.