akcs.scotty@hpcvbbs.UUCP (SCOTTY THOMPSON) (05/05/91)
John, here are some possible commands for the ADCM-48 (cmds #9-#13)
REPEAT (2-byte Command)
Repeats the next command the number of times
given in the second argument.
SCAN_ANALOG
Sequentially scans Analog Inputs 1-4 at .01
samples each and returns a 4-byte value
corresponding to Analog Inputs 1-4, respectively.
PUT_SERIAL (2-byte Command)
Sends the serial representation of the
parallel byte given in the second argument to the
Digital Output referenced in bits 2 and 3 from the
first byte of this command. The bits will be
clocked on the falling edge of the Digital Input
referenced in bits 1 and 0 from the first byte of
this command.
GET_SERIAL
Receives the parallel representation of the
serial byte received from the Digital Input
referenced in bits 2 and 3 of the command. The
bits will be clocked on the falling edge of the
Digital Input referenced in bits 1 and 0 of the
command.
BATCH
0: Indicate Batch Header
1: Indicate Batch Footer/Execute Batch
The ADCM-48 will store commands in it's
command line buffer upon encountering the BATCH_0
command and continue to store commands (without
execution) until receipt of the BATCH_1 command.
Upon receipt of the BATCH_1 command, the entire
batch will be processed. Using the REPEAT and
BATCH commands can allow the HP to set-up an
initial programming sequence to the ADCM-48 and
simply read and process the data without re-
transmitting commands.
Also, the pin-diode idea sounds like a good one. Maybe putting a
bandpass filter on the Rx photodiode will help noise. Radio-shack has a
part that includes the pin-diode, hi-gain amp, band-pass filter,
demodulator, etc. which would fit nicely in the amount of space that you
already have allocated for the Rx transistor and support components. I
am able to verify receipt of I/R transmissions over 20 feet away with
this unit. Unfortunately, the bandpass is set to 100KHz, but reversing
the output (can't remember exactly how I did it) will bypass (seemingly)
the filter and still give good noise immunity and sunlight rejection
while still allowing "AC" signals to pass nicely.
It was a pleasure talking with you. Thank's again for your advice.
Good luck to you--and let me know how the conference is if I'm unable to
make it!akcs.jwtrav@hpcvbbs.UUCP (John Wettroth) (05/19/91)
thanks again scotty. i have played with the radio shack and other tv remote control receive modules. unfortunately the hp-48 calculator to calculator protocol has no high frequency carrier. the printer link includes a 32768 hz carrier and is suitable for use with a demodulator. the designer of the calculator to calculator link wanted something quick and dirty which means no carrier and little checking. the printer interface protocol has about 50% overhead in parity bits and is rather slow. i considered it but opted for the quick and dirty route. thanks for the command ideas, i'm going to study them and possilbly implement some. if i get something together thats solid, i'll send you one for evaluation. thanks. hope to see you at corvalhalla in august!