Serial Port Errors with Humax 5400 + PC emulator (Mac)

[g4guy]

Hi,

(sorry in english my dutch is not yet good enough...:-/).

Before I go out buy an old 99 Fl. x486, lets see if anybody was succesful with this "strange setup"

I'm trying to set up serial connection between my Mac G4 and my Humax 5400.

I have MacOS 9.2.1, VirtualPC 4.02 running Windows 98, plus a Keyspan Twin USB-Serial adapter plus a Serial null modem cable (DIN 8 to DB9 which I personally soldered )

Now, before I try to use it for FW upgrade I tried reading the settings from Humax to PC (just to make sure the serial connection is OK)

So I start FormulaV3 and press go, the transfer goes fine for a while than I get E-ut error on the STB and on the FormulaV3. Slowing down the baud rate down to 19200 in FormulaV3 settings does not help, it starts OK and then after a while it stops with serial error

Now it could be :

1)cable wrong lead/wiring

2)cable too long

3)incorrect setting of Windows 98 in emulator,

4) incorrect settings in Keyspan MacOS about the serial port emulation...

aaargh !

Has anybody ever tried that ? Please !

 

[wizzaerd]

Hi g4guy,

You're forgetting one option:

5) Not enough power at the ports of the keyspan.

This happens with modern hardware. I had the same problem with a modern laptop.

Using an older P266 desktop no problem at all. The same applies for older Mac's with an onboard serial port (PM7500+VPC+w98 works fine with many serial devices).

Perhaps the solution is using a PCI-board, if available.

 

[g4guy]

Yes @!@!@!

I wonder if you are right. This is a potentially good explanation.

1) Would a shorter cable help ? (minimize losses ?)

2) The RS-422 mac serial should not have any problem receiving data as it works with differential signal (as opposed to absolute polarity of old RS-232) however it is possible as you point out that the TxD signal has not a voltage level high enough to drive the Hummy serial RxD line.... hmmmm

Can I measure it in any way ? (Oscilloscope ?)

g4guy

 

[g4guy]

After talking to "experts" it looks it is an issue about not having exclusive control of the Serial I/F (as it is emulated) and therefore not able to respect a strict timing required by the Humax.

Unfortunately (and this is really a crappy design on Humax part) HW handshacke is not used (like is done with the majority of the Serial instruments) so not having exclusive access (the same issue when you want to use a SC programmer) causes timing problems...

I'll try to see if it is possible to find/write some open source *nix SW to compile under MacOSX (and why not Linux)

 

[sebastopol]

IMHO it is a timing/handshaking problem:

I'm using an iBook + VPC + keyspan PDA adapter and have got problems with the connection to my HUmax receiver and progger.

I'm also using the same setup to connect my Mobile Phone, Phone Switchboard (telefooncentrale) and lego MindStorms. With those I've got no problem ...

The problem seems to be lesser when you install de Keyspan Drivers on the Mac, and connect COM1 to the printerport, and this opposed to installing the Keyspan Drivers under Windoze.

The one thing that ***really*** helps is being quick with tansfering data, and resetting both the program on the pc as the humax/progger when you encounter the problem: the longer the connection is open/the more bytes that are transferred, the bigger your chance for problems.

Good luck,

Sebastopol

 

[satjan]

hehe het board krijg nu een engels tintje !! geen slecht idee mischien een 2de funboard in het engels mischien iets voor de heren Mod's van dit board om eens over na te denken .

Groeten .