On Mon, 17 Jul 2000 17:41:54 +0100 Michael Polak wrote:
> I have checked by BIOS, and it declares Irq 4 to be reserved for COM1.
> But I checked the modem library used by MINITERM, and it claims COM1
> is Irq 2 !!!
>
This business of which COM port uses which IRQ has always made me
wonder - especially when poeple start talking about IRQ conflicts.
In the much saner world of 8-bit microprocessors, there is very often
only 1 IRQ line and ALL peripherals have to connect to it if they want
an interrupt serviced. When the CPU senses that the IRQ line has been
waggled, it checks all peripherals connected to the line to see which
was requesting an interrupt.
Just in case anyone's about to ask: NO, it doesn't matter whether the
CPU has 8 bits or 80. It can still check multiple peripherals to see
which one interrputed.
Now - surely, even in the world of PC software, it should be possible
to connect the COM1 and COM3 (or any combination of COM1 to COM4) UARTs'
interrupt pins to the same IRQ line and have the CPU check which UART
requires a service when that IRQ line goes active. After all, IRQ lines
are in short enough supply as it is. My IRQ5 is required for the sound
card. I have 3 LPT ports and 3 COM ports, just to compound the problem.
Is this 'IRQ conflict' problem just another example of the average
PC software writer being blissfully unaware of what the chips are
actually doing in real life??
Ron.
> I want to override all possibly different COM port defaults, used by
> setup screens, CORE.EXE, WIZARD.EXE, COMTOOL.COM, MINITERM.EXE and
> EPPPD.EXE, to avoid any future confusion. I even added second alternative
> description of the ports to setup screen, which mentions corresponding
> Linux style /dev/ttyS0 to /dev/ttyS3, so Linux gurus can help DOS users
> to setup Arachne ;-)
> Now I would need to know, if following table of port address/irqs is
> really 100% correct - well, WIZARD is anyway testing some more
> combinations, so COM3/COM4 values are not really problem. But COM1 and
> COM2 are same on all PCs, I think, and I don't want to add unecessary
> confusion...
> int default_base[4]={0x3f8,0x2f8,0x3e8,0x3f8};
> int default_irq[4]={4,3,4,5};
> - --
> Michael Polak: [EMAIL PROTECTED]
> Arachne Labs: http://arachne.cz/
> My mobile phone - up to 160 characters: [EMAIL PROTECTED]
> ------------------------------
> Date: Sun, 16 Jul 2000 14:21:42 -0400
> From: Terri FitzSimons <[EMAIL PROTECTED]>
> Subject: FREEWWWEB (lack of) connection
> I have recently established an account on FREEWWWEB, but ARACHNE
> doesn't
> seem to be able to connect with the web using that ISP. I can log on to
> FREEWEB and load the packetdriver, but the home page -- indeed, any page --
> does not display. ARACHNE just hangs until I cancel manually. Can anybody
> tell me what's happening here?
> I can get on the web through CompuServe, but not FREEWWWEB.
> Here's the relevant part of the .cfg file:
> [connection]
> Profile FREE.ACF
> Connection @epppd.exe > PPP.LOG
> Hangup @termin.com 0x60>NUL
> ;Connection @dialer ... Arachne will display DialPage and call dialer
> ;Connection READY ... Arachne expects resident packet driver
> ;Connection NUL ... Do not start TCP/IP (run "arachne -c" to force
> this)
> [dialer]
> DialPage file:ppp_init.htm
> Dialer @EPPPD.EXE > PPP.LOG
> TerminalWindow @MINITERM.EXE
> UseTerminal Yes
> Port 1
> Irq 4
> Base 0x3f8
> Mode 8N1
> Speed 38400
> InitString AT&F
> DialString ATDT
> PhoneNumber 930-1555
> Autologin no
> Waitfor 1
> Response1
> WaitFor2 Login:
> Response2 \u
> WaitFor3 sword:
> Response3 \p
> WaitFor4
> Response4
> WaitFor5
> Response5
> ;/noint/go:pppconnect
> PPPusername xxxxxxxxxxxxxxxxxxxxx
> PPPpassword XXXXXXXXXXXXXXXXXXX
> ;Base values: Default|0x??? (eg. 0x3e8)
> ;Mode values: databits/parity/stopbits (eg. 8N1)
> [tcp/ip]
> IP_Address %MYIP%
> IP_Grab IP address set to
> NameServer 63.24.150.127
> AltNameServer 63.24.117.63
> Gateway 0.0.0.0
> AltGateway 0.0.0.0
> Netmask 0.0.0.0
> TCPconfig PPPTCP.CFG
> ;IP_Address n.n.n.n ... fixed IP address
> ;IP_Address PPP ... for PPP.EXE and PPPD.EXE (get address from
> PPP.LOG)
> ;IP_Address BOOTP ... WatTcp attepmts to use BOOTP protocol
> ;IP_Address %enviro% ... Minuet style (enviroment variable, like %MYIP%)
> ;IP_Address WATTCP ... use ONLY values from TCPconfig (variable "my_ip")
> ;IP_Grab string ... prefix of IP address in PPP.LOG ("IP address set
> to")
> ;TCPconfig filename ... name of WatTcp configuration file (often
> WATTCP.CFG)
> ------------------------------
> Date: Sun, 16 Jul 2000 20:46:13 +0200 (MET DST)
> From: Bernie <[EMAIL PROTECTED]>
> Subject: Re: Finalizing Arachne COMport defaults...
> Michael wrote:
>> int default_base[4]={0x3f8,0x2f8,0x3e8,0x3f8};
>> int default_irq[4]={4,3,4,5};
> EPPPD defaults to 3 on COM4, I would also like to know what the true values
> are...
> However I still think you should read the default_base values from the BIOS
> when in run-time, they can be changed... (atleast I think I can do it)
> //Bernie
> http://bernie.arachne.cz/ DOS programs, Star Wars ...
> ------------------------------
> End of arachne-digest V1 #1194
> ******************************
