[linrad] RE: Linrad-hardware

[Leif Åsbrink <leif.asbrink@xxxxxxxxxxxxxxxxxxxx]

Hi Graziano,

I send this on the mailing list because I think it 
may be of interest to others.

> I have finished the Dual-Power-Supply for Linrad
> hardware.:)
> For the first time i have used the
> WSERX2500+WSERX10700+WSERX70,
> but when i setting the frequency in the  WSERX10700 or
> in the WSERX70
> the unit set the frequency, but Linrad
> produces ERROR:RX10700 or ERROR:RX70. 

Use the function "Z=Hardware interface test"

The screen you arrive at will allow you to
toggle the data pins of the parallel port
to form 256 addresses. The default definitions
specify the WSE units as addresses using a single
bit so there is no need for a address decoder until
you want to control a transmitter relays and other 
things.

If you enter "4" to toggle data bit 4, the status on
pin 6 of the d-sub will go high (+5V). The interpretation
after the addres word change from Unkn to RX10700 which
means that the raised pin is expected to raise the
select pin on the RX10700.

You may now  use the "C" key to toggle the clock to
clock the current status of the data pin into the RX10700
unit. Use "D" to toggle the status of the data pin and 
again use "C" so you can see that the status of the 
control pins changes as expected.

The pin that Linrad expects to get the status on is red
on screen. There are 5 lines in hwaredriver.c by which
you can select which pin you want to use.
#define USE_PIN11_BUSY_FOR_ACKNOWLEDGE
and similar. Note that only pin 10 (acknowledge) has 
a builtin pull up resistor. When the other pins are
used a pull up resistor is probably needed. Could be
1 kiloohm for example. Very uncritical.

The default version of Linrad uses pin 11 (busy) because
I made the mistake once on my Pentium III to plug the cable 
into a unit that was not grounded already. The electrostatic
discharge destroyed the 74HC03 in the WSE unit as well as the 
parallel port input stage for pin 10. I then moved from pin
10 to another one and it happened to be pin 11.

That is why my system is still wired for pin 11 (actually 
in parallel with pin 10 to use the builtin pull up resistor)

By use of the "Z=Hardware interface test" and a volt meter
it should be pretty straightforward to investigate the 
simple serial interface of the WSE units.


73

Leif / SM5BSZ




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