Hi,

What is the AUX device used for on msx? Are there any programs around that use it? I found that the diskrom provides two hooks for it; reading and writing.

How exactly do you create your own device. I know the device handle in the rom header should be used. However, the diskrom does not use it although it does provide 5 devices (PRN, LST, CON, AUX and NUL). I could not find much information about it.

Any documentation about the subject is welcome.

Thanks in advance.

Iirc the official ascii rs232 uses the aux..

That's strange... The AUX device is provided by the diskrom. An rs232 device provides its own device (COM) why would it need to use the AUX device?

The diskrom provides for the AUX device, because of the CP/M compatiblility. CP/M has some functions for the AUX device. The diskrom provides some hooks, to link AUX to the MSX-Serial (&HF327 for AUX in, &HF32C for AUX out).

@kwik: There is no COM device specified

I did find some information on creating a device handler in the msx technical handbook. It is specific for rs232 devices, and doesn't go into much detail. Does anybody know a good source on how the create a device handler?

I'm interested in the parameters of the following functions.

        dw open                 ;  0
        dw close                ;  2
        dw randomio             ;  4
        dw seqOutput            ;  6
        dw seqInput             ;  8
        dw loc                  ; 10
        dw lof                  ; 12
        dw eof                  ; 14
        dw fpos                 ; 16
        dw backup               ; 18

If you want to know more about MSX-serial programming, you should read this:
www.classicgaming.com/epr/msx/232bcal.txt
To use this info, you should know something about using Extend BIOS Calls (&HFFCA), but that is available in the MSX technical databook. If you need more help, let me know.

This is what the dos2 reference manual says about AUX : The AUX device mentioned above does not do anything by default, but a routine may be hooked into it so that it refers for example to a serial driver. The NUL device does not actually do anything; output characters are ignored and an end-of-file is always input. The LST and PRN devices are identical.

If I remember correctly, there is a offical tool which connect AUX to the MSX-serial by means of the mentioned hooks. May be it is on Datapack disks, but I am not sure.

@zeilemaker: Thanks for you link. Together with the information in the MSX Technical Handbook, it provides all the info i need (i think). I was a bit confused about the difference between a standaard MSX rs232 and a device. If i am correct, the MSX rs232 is just another device (called at 0x4006), but to make it a standard MSX rs232, it should also be accessible with an EXTBIO call? Right?

Going to use that for the USB stuff?

Yes, that is the idea. Nowind provides a connection to the pc. Our primary goal was to use it to access disk images. But now that that works fine, we are thinking of implementing other functions. Supporting RS232 would be a nice feature i think. If it works the msx can access rs232 devices that are connected to the pc. It will perhaps also be possible to connect to the internet directly (without an Obsonet...). But i'm not into using the TCP/IP stack on msx.

Another feature that i'm working on right now, is redirecting AUX to the host. Its stdout and stdin can then be used to communicate with the MSX. The AUX stuff is easy to implement, but the rs232 is much more work. I'm now looking into EXTBIO. I've never used it before.

I've already made my own device (0x4006) entry and can do this in basic:

open "nowind:" for output as #1
print #1, "Hello host!"
close #1

Nice.. so you can also copy files to aux in dos

Quote:

If i am correct, the MSX rs232 is just another device (called at 0x4006), but to make it a standard MSX rs232, it should also be accessible with an EXTBIO call? Right?

Well more or less. The 0x4006 thing, that is a MSX-BASIC device handler. Not used outside BASIC. The EXTBIO call is used typically in a machinecode program, so it's usage independ of BASIC.
By the way, a quick way of testing for MSX-serial is:

ld a,(0xFB20)
and 1 ; is EXTBIO available ?
jr z,noserial ; nope, no serial
xor a ; assume no channels
ld d,8 ; deviceid MSX-serial
ld e,1 ; function 1 (get number of channels)
call 0xFFCA
or a ; number of channel <>0 ?
jr z,noserial

; msx serial found

Thanks, i'm implementing the EXTBIO part right now. I have one other question. What software uses the msx-serial?