QRZ! Ham Radio 3/QRZ Ham Radio Callsign Database - Volume 3.iso/digests/tcp/930229.txt

Internet Message Format | 1994-06-04 | 16KB

Date: Mon,  6 Sep 93 04:30:07 PDT
From: Advanced Amateur Radio Networking Group <[e-mail]>
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Subject: TCP-Group Digest V93 #229
To: tcp-group-digest


TCP-Group Digest            Mon,  6 Sep 93       Volume 93 : Issue  229

Today's Topics:
                More than 3 packet drivers ? (2 msgs)
                      Problems with pa0gri 2.0p
                       RE PI CARD PROBS SOLVED
                    scc&hi speed packet , part 1/2
                    scc&hi speed packet , part 2/2
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----------------------------------------------------------------------

Date: Mon, 6 Sep 1993 10:31:40 +0930 (CST)
From: Rob Mayfield <[e-mail]>
Subject: More than 3 packet drivers ?
To: [e-mail]

Hi All,

Just wondering if anyone has had success with 5 or more packet drivers
in some of the later nos versions (jnos 1.10x?). Ive managed to get what
looks like a working compile, but previously have had stability
problems. The user wants 5 ports on bpq, and doesnt want 2 images of nos
running (for obvious reasons).

I'd be interested in hearing from anyone who has this running. We have
an application where they guy wants 7 drivers, but we'll work on the 5
first :-)

73's ... Rob
--
rob mayfield vk5xxx/vk5zeu  po box 46, henley beach, south australia, 5022
packet radio vk5xxx@vk5xxx.#adl.#sa.aus.oc  wire [phone]w [phone]h
i-net  [e-mail]   or  [e-mail]

------------------------------

Date: Sun, 5 Sep 93 23:06:11 -0400
From: Jim De Arras <[e-mail]>
Subject: More than 3 packet drivers ?
To: Rob Mayfield <[e-mail]>

> Hi All,
>

> Just wondering if anyone has had success with 5 or more packet drivers
> in some of the later nos versions (jnos 1.10x?). Ive managed to get what
> looks like a working compile, but previously have had stability
> problems. The user wants 5 ports on bpq, and doesnt want 2 images of nos
> running (for obvious reasons).

I have 5 packet drivers working, no problem!  You just need to edit 3-4 files
to increase the amount available.  The .h file alone is not enough, you have to
add the needed copies to the .asm and the .c files.
>

> I'd be interested in hearing from anyone who has this running. We have
> an application where they guy wants 7 drivers, but we'll work on the 5
> first :-)
>

> 73's ... Rob
> --

> rob mayfield vk5xxx/vk5zeu  po box 46, henley beach, south australia, 5022
> packet radio vk5xxx@vk5xxx.#adl.#sa.aus.oc  wire [phone]w [phone]h
> i-net  [e-mail]   or  [e-mail]
>

>

Jim

------------------------------

Date: Sun, 5 Sep 93 12:23:13 CST
From: [e-mail] (Cuenta Publica)
Subject: Problems with pa0gri 2.0p
To: [e-mail]


Hi!! I installed the pa0gri nos with a jnos configuration yesterday, but when
i try to do an 'attach asy' command the program hangs. Somebody knows what
happens?? I am using pa0gri 2.0p . The configuration works fine with the
wg7j code.

Also i have problems connecting two machines via the internal slip drivers.
I can do it, but only with the clarkson packet drivers. I cannot connect
two machines by a dialup connection by slip,i can only by ppp. Somebody knows
how to do it ???



  Thanks for any response

   Roman

Roman Torres
Programmer
[e-mail]

------------------------------

Date: Sun,  5 Sep 93 11:00:00 -0600
From: [e-mail] (Karl Ebel)
Subject: RE PI CARD PROBS SOLVED
To: [e-mail]

hello all,

thanks for all your replies. All of the ideas are indeed
potential problem areas.

We followed the advice from Dave:

    120 ohms across jumper W6 at DDIOW position
    220pf from U2 PIN 6 to ground.

It works perfectly with a 386DX-40MHz board. And it still
works with the former inuse 486DX-25MHz board.

Thanks to Dennis for his inside description of the problem.

NOS in a DOS-Box of OS2 V2.1 is still crashing. We are
studying the problem.

So thanks to all helpers from the group:
    DF5KO, DJ8JG, DL5KAW and me DK8GD.

73 de Karl.


+-------------------------------------------------------------+
|   Internet ..:  [e-mail]                          |
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+-------------------------------------------------------------+








It works with a 386DX-40MHz. And it
still works with the forme inuse board 486DX-25MHz.
Components are 120 ohms and 220pf.

Thanks from the group:

   DF5KO, DJ8JG, DL5KAW and me DK8GD.


73 de Karl.


+--------------------------------------------------------------+
|   Internet ..:  [e-mail]                           |
|   AMPRNET ...:  [e-mail]     44.130.32.1        |
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------------------------------

Date: Sun, 05 Sep 93 08:42:25 UTC
From: [e-mail]
Subject: scc&hi speed packet , part 1/2
To: [e-mail]

Hi Folks

I recently compiled a small report on SCC card modifications
for hi speed packet . Guess you may be interested .
Split it up in 2 parts , here is part 1



SCC card modification for use with hi speed baudrates
-----------------------------------------------------




1- Purpose:

To improve performance of time response scc card so that
speeds up to 38400 baud can be used
Exchange of experience and knowledge on hi speed packet with
scc card .


2- Introduction:

The pa0hzp scc card is standard equipped with 8530 scc chips
and performs very well with baudrates 4800bd - 9600 bd .
However some mod's are needed to increase usable speeds up
to 38400 .
This document is not a spic and span upgrade manual but
describes problems and modifications personally
encountered .

If you want to have the best , buy the most recent state of the art
stuff somewhere .
If you want to get the most out of you exsisting scc card ,
and have fun , keep on reading .




3-Areas of improvement


3.1- Optocouplers

Optocouplers are usable up to 9600 bd or so but cause problems
at higher speeds . This due to optocoupler response but also
cable capacitance . Using standard 10 wire shielded 'serial port'
cable with a length of 3 meters did not work at 38k4 .
Shorten this cable to a minimal length ( 30 cm or so ).
Experiments with flatcable may be usefull too ( didn't try)

Also optocouplers have been removed at the hi speed ports.
A 74LS00 in the 38k4 modem now directly drives the TTL ports
on the scc card .
For this, the txd and rxd tracks on the scc card, going
to/fro the modem were cut and directly connected to the
74ls14 gates .
Even better is to use a DIL solderable adapter which can be
inserted in the IC socket . Keeps the scc pcb original .

Modify your modems so that it is TTL driven ( remove the
resistors etc ) .
As a consequence, from now on modems may only be disconnected
with the power on ALL parts of your system shut down !
Also connect the return path ; mount a wire from the 'earth'
connection at the modem side of the 37 pens D shell connector
to the earth on the scc card .
Verify with an Ohm meter ( to pen 7 of any 74ls14 ) that it is
the earth and not the +5 Volts line ....

Doublecheck all mod's made since there is a real risk of
blowing your scc or pc now ....




3.2- (E)SCC chip

The SCCchip ( 8530 ) is a standard chip used for synchronous
datacommunication ( packet ) as the 16450 is standard used
for asynchronous communication ( serial port ) .
Both generate interrupts to your CPU for every character received ..
So if the serial port receives a block of data with lenth of 1024
bytes , 1024 interrupts are generated
Any other activity in the pc generating interrupts during reception
of this data block may cause that characters are missed .
With synchronous transfer , this leads to eg Rx Overruns and
Tx underrruns .
Solution : use of fifo buffers .
The 85230 from AMD or Zilog incorporates 8 byte receive and 4 byte
transmit fifo buffers .
This allows data to be stored in the fifo so that the cpu is able
to fetch the datablock complete when returning from another task .
( compare with improvement replacing 16450 with 16550 usart ) .
Installation ; just remove the 8530 from the scc card and insert
the 85230 ( zilog or amd ) . Observe static discharge precautions .
You may replace only one or both chips if you like .
The escc is supported with net from pe1chl
Use a recent version( 921018lt.exe or upwards should support the
escc ) .
In the autoexec.net the  ' attach scc ' must be replaced with
                         ' attach escc '
for those channels equipped with the 85230 .
Tests run on a 40 Mhz 386 gave no space or overruns at 19k2 but
did do so on 38k4 .
After 'attach escc ' no overruns or space errors anymore
( tested with 921018lt.exe )

Recently also the SCC driver for Linux ( pe1nnz ) was adapted on an
experimental basis to support escc, first tests reduced tx overruns from
roughly 300 / Megabyte back to nil ( 0 ) or occasionally one
 ( tested   at 38k4 ). RX improvements still under construction .

Also NOS may support escc, a version made by pe1mnl also
supports escc on experimental basis ( is not the final version yet,
same trick used as with the scc driver for linux )

End of part 1
----------------
73 de harry pa3aou@pi8hvh




PLEASE reply to the list, NOT to the From: address
because this mail is sent through a one-way gateway!

------------------------------

Date: Sun, 05 Sep 93 08:43:19 UTC
From: [e-mail]
Subject: scc&hi speed packet , part 2/2
To: [e-mail]

Improvements for use of scc card on hi speed packet part 2 :
------------------------------------------------------------


3.3- Clock speed SCC card


Increasing the clock speed on the scc card will also
improve the response .
The clock speed must be a multiple of 2 in order to generate
the proper baudrates . With an 8530 usually a 4.9152 Xtal is used .
Using the 85230 escc will allow to use higher clock speeds .
The amd am85c230a is specified to run on 8.192 MHz scc clock speed .
This requires both chips on the scc to be escc .
Also modify the clock speed given in the ' attach  escc '
statement used to initialise the scc card .

Maybe it is possible to directly mount a 8.912 xtal , I didn't
test this .
I used parts ' available' which happened to be a 19.660800 MHz
oscillator module .
It is mounted at the place of the 4.912 MHz quartz .
 __________
| 1      2 |  top view : x = dot
|          |             1 = + 5 Volts
| x      3 |             2 = TTL output
 ----------              3 = earth
Before, remove the 4.9 MHz quartz as well as R20,21 ( 1 kOhm ) and
C 1 ( 1 nF ) .
Cut the track from the oscillator output going to the 74LS368 .
Cut the track coming from the ESCC chips at pen 20 ( clck ) going
to the 74LS368 .
An extra 74LS93 is mounted near the edge connector ( empty socket)
The 14 pens IC socket is mounted closest so that pen 7 is free
and pen 14 at the +5 Volts position .
Before inserting the IC, lift pen 14 !! .

Unlike most TTL IC's , the 74LS93 does NOT have its +5Volts
supply on pen 14 ..........
Connections as follows:
pen  1  : connected to pen 12
pen  2  : to earth
pen  3  : to earth
pen  5  : to +5 Volts
pen 10  : to earth
pen 14  : input from Oscillator block
Assuming frequency = input from oscillator block on 74LS93 pen 14 ,
available output signals are now :
Qa = pen 12 = frequency /2
Qb = pen  9 = frequency /4
Qc = pen  8 = frequency /8
Qd = pen 11 = frequency /16

At present the scc runs on 4.9 Mhz  ( Qb ) since only one ESCC
is present .
Make sure to specify this frequency in the  'attach scc  '
initialisation .
Performance improvement here unknow yet  ..
Note , use 74 LS 93  , the 74 L 93 has a different pin layout ...


For sure you may want to use another IC , no problem . Just
observe that it will run on the higher frequency ( cmos may be
insufficient )
74LS74 ( dual D-type flip flop ) , 74LS290 or 74LS293
( binairy counters ) are some alternatives .
Be creative and check your databook for exact pen layout !


3.4- Stop unwanted interrupts

Depending on the transceiver you have the Rx part may produce
noise even when no carrier is received .
The FT290 for instance leaves the receiver on when it transmits .
Often I can then trace my transmitted packets .
Another set miraculously produces extra noise in the lf receiver
partduring transmit .
As result Rx interrupts are generated during transmit
Kill those interrupts !
Use an extra 74 LS 00


original                          added
.............. --------------------------------------------------


74 hct 132     o to rest of original part
__      ___   |
PTT-|--|   |  |             o rx data from modem
    |--|   |o-|             |
       |   |  |   -----     |   ------         ------
        ---   | 1|     |    | 5|      |      9|      |
              |--| N1  |3    --| N2   |6   |--| N3   |8
              |--|  *  |o------|  *   |o---|--|  *   |o---R 1---o
                2|     |      4|      |     10|      |       to scc card
                  -----         ------         ------        rx data

+5 Volts at pen 14
ground at pen 7

*   = added 74 LS 00 gates
R 1 = 470 Ohm for scc cards with optocoupler
      discard R 1 for direct TTL driven scc card ( modified )

The modem cannot be used for fullduplex operation after this change !

The circuit can be simplified by offering a PTT/NOT directly to
pen 4 of N2 ( low state when transmitting ) and
leaving out N3 ( not needed in for AX25 HDLC coding , usually NRZI )
I just put them in for level conversion to / from TTL .


3.5- Check your PC

Not only focus on the scc and software .
Doublecheck your PC setup .
Experiments with reducing wait states to 0 and increasing
ISA AT bus speed may cause troubles   or    improve
the overall performance .
Check it ! It's worth trying .




4- Thanks

Thanks to those helping me with supplying material en spiritual
support .
If you find bugs in this article , send it to


ax25:  pa3aou@pi8zaa.#nbo.nld.eu
smtp:  pa3aou@pi8ehv ( local ) or  pa3aou@pi8hvh



73 de Harry
3-9-93






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because this mail is sent through a one-way gateway!

------------------------------

Date: Mon, 06 Sep 93 06:50:48 GMT
From: [e-mail] (Ian Wade)
Subject: Subscribe
To: [e-mail]

Subscribe

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------------------------------

End of TCP-Group Digest V93 #229
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