As far as I can tell the decoder will not sync to correct time, unless it’s using the Galleon Systems Time sync version 3.2 or later.
This software will not only allow you time sync with radio feed(Anthorn MSF 60Hz) but also GPS and internet feeds.
It has to see the command(s) I called up to get the function of data output from the MCM-RS232,the final command is character carriage return (hex 0d) for the MCM to execute the command function.
Only the four lower bits of each command and parameter character are used.
For instance the characters “?” “O” and “o” have same effect,(The exception is final carriage return which is decoded by considering the seven lower bits, completely decoded)
We are talking here as to the first data the MCM decoder has to see for a expected request from the PC,
so sync processing can start with a “time” output.
You have called up that your MCM -232 is giving you a time output, unless your data request is as per the output will none valid.
The MCM-232 then requires both positive and negative voltage out of the PC.(not talking here with the MAX232)
the positive voltage is supplied by the DTR line, one of two ways can be used to supply the negative voltage, PC communicates with MCM by sending ACSII characters. Negative voltage supplied by TxD line.
Back to the buffers, use the RTS line to be held low(add to program this function)when the MCM 232 is sending “Time”( can also use the MAX232.
The reply from the MCM232 is as I called up in the previous post, not time data raw.
just a note here the MCM reply for combined time date is a sequence of ASCII characters (terminated by carriage return character.
The character set in the MCM 232 is very limited to 0…9 : ;<=>? information contained in four lower bits, so bit 4 and 5 of every reply character are Binary "1"s bit 6 is Binary “0” and bit 7 is the even parity bit.
The most important aspect here is the MCM232 reply characters cannot be interrupted during the reply, so all characters have to be taken by host PC.
Now there is a more simple way of doing the above.
This may be where your software came in to play which could be why your MCM232 was sort of giving data out .
The more simple method is pull the TxD voltage high,when normally the TxD voltage is low(inactive) if the TxD voltage is high on the start of a second, the MCM232 will feed out it’s message, this can take upto 1 second due to the first start bit of time/date information sets the beginning of the second.
If the TxD line is held high continually MCM 232 will feed out time date information every second.
Beware here as the current consumptionMCM23 will be higher during data output,for aprox 600 ms upto 200uA.
Now all that required is to get the handshaking done with theMCM232 , this is by each character received by MCM is echoed, the next character must not be feed out before the echo of the preceding character plus 10 ms.
Recognising input characters is by checking both start bit and two stop bits at MCM, then the eight echoed data bits remain unchanged, regardless whether or not parity is even or odd.