[amsat-bb] A MicroController-based T/R Sequencer

[Bert <ve2zaz@xxxxxxxx>]

Hello to All,

I am about to wrap up the design of a
microcontroller-based T/R sequencer board. But I
thought I would ask the Amsat folks for any
suggestions or bold omissions before I release the
design and publish it one of the ham magazines. My
intent is to distribute a PCB along with a
pre-programmed microcontroller.

So here are some of the features of my design:

- It is a microcontroller-based approach, which brings
a lot of features and flexibility into the design,

- The Sequencer controls up to six outputs; these can
be configured as either normally open or normally
closed.

- All outputs switch through a solid-state relay; no
mechanical relays are used. Currents up to 500mA can
be switched, depending on the solid-state relay
populated.

- Push-To-Talk (PTT) logic can be configured for
either active-high and active-low states,

- User-set delays are inserted between any two output
state changes. Delays are set for both the RX-to-Tx
and the Tx-to-Rx sequences.

- Switching feedback signals are available to the
microcontroller for confirmation purpose. A timeout
feature will abort the sequence if feedback for an
output is not detected within a pre-defined delay.

- While under operation, all inputs and outputs are
DC-isolated using opto-couplers.

- The Sequencer provides a visual indication of each
output’s state via a series of bi-colour LED’s,

- It also emits various tones via a piezo sounding
device at switching completion, for feedback alarming
and as a Transmit timeout alarm.

- A watch-dog feature ensures that the output are
promptly released if the firmware is ever to crash,

- A Windows-based tool allows to (re-)configure the
Sequencer in minutes via a RS-232 link.

- All settings are saved in non-volatile Flash memory.

If you would like to communicate your thoughts on it,
send me an email directly at ve2zaz@amsat.org.

Thanks!

Bert, VE2ZAZ
amsat #27668
http://www3.sympatico.ca/b.zauhar
ve2zaz@amsat.org
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