[time-nuts] PRS 10 and serial port communication

Mike Cook michael.cook at sfr.fr
Fri Mar 4 04:34:54 EST 2016


You could try « RC 1 » blind. 
That will reset the EEPROM values to factory settings. However I do not see any settings for serial rates, so it may not help. 
From your oscilloscope, it should be possible to determine stop/start and baud rate and decode the binary data.
I have done this in the distant past.
There are web resources. Check out <http://electronics.stackexchange.com/questions/17562/how-to-read-serial-data-from-oscilloscope>
for example.

Mike

> Le 4 mars 2016 à 09:36, Philip Zahariev via time-nuts <time-nuts at febo.com> a écrit :
> 
> Hi Jarl,
> 
> As I already write PRS10 is configured as serial communication. With oscilloscope I can see serial signals, but when enter this signal in computer with TTL level USB2serial converter all information is repeatable character unknown for me and not as described in manual. For test i change baud rate, number of stop bits, number of bits without success. Also trace signal to U302 MC68HC11 pin 20 and 21 and both TX and RX are the same as on J100 (external connector) - time/period and amplitude has TTL levels. For me looks like internal ROM has incorrect bits or processor is not in normal state and response from serial port coming from different subroutine. 
> I expect hints how to check processor state. Or how to push processor in state where will have normal serial communication. 
> 
> Best regards
> Philip
> 
>> On 4.03.2016 г., at 9:35, Jarl Risum <jarl.risum at gmail.com> wrote:
>> 
>> OK, Philip
>> 
>> If you have confirmed with a Oscilloscope that no RS-232 communication is present on the TXD output pin, I sugggest you check the status of R247/R248 and R353/R354 - see the manuals chapter on "PRS 10 Applications" (page 20), description of pin 4 and pin 7.
>> 
>> Good luck
>> 
>> Jarl
>> 
>> 2016-03-03 20:08 GMT+01:00 Philip Zahariev <philip_zahariev at yahoo.com>:
>>> Hi Jarl,
>>> 
>>> 
>>> 
>>> Of course I use TTL level USB serial converter. Unfortunately, as I write no communication, or at least not what I expect.
>>> 
>>> 
>>> 
>>> Best regards
>>> 
>>> Philip
>>> 
>>> 
>>> 
>>> From: Jarl Risum [mailto:jarl.risum at gmail.com] 
>>> Sent: Wednesday, March 2, 2016 11:49 PM
>>> To: philip.zahariev at yahoo.com; philip_zahariev at yahoo.com
>>> Subject: PRS 10 and serial port communication
>>> 
>>> 
>>> 
>>> Philip,
>>> 
>>> The outgoing RS-232 port from PRS 10 is a TTL inverter with an approx. 1 kohm series resistor. 
>>> 
>>> See diagram of the microcontroller board, upper right corner.
>>> 
>>> For this reason you may have problems reading the outgoing RS-232 messages with a standard RS-232 PC input. But you may see the transmission taking place with a oscilloscope.
>>> 
>>> I have had the same problem with my PRS 10 and solved it with a simple 2 transistor non-inverting amplifier fed from a +12V source.
>>> 
>>> If interested, I can send you the diagram.
>>> 
>>> Cheers from
>>> 
>>> OZ9MO / Jarl
>>> 
>> 
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