RS-485 with STC12C5A60S2 MCU issue

[mjawed]

Hi Friends,
I am looking for some help regarding the PARKING GUIDANCE SYSTEM (based on STC12C5A60S2 MCU - CHINESE Manufactured) with RS-485 interface for the PC serial /USB port, as well as for the attached Ultrasonic Vehicle / Car presence sensor with RED/GREEN LED indicator light modules.

The problem is that the mentioned Baud Rate (as described in User Manual) for both of the RS485 serial ports are 4800 for Sensor Port and 9600 for PC serial interface (via USB to RS485 converter / adapter), respectively.

But, using the standard SERIAL TERMINAL Apps for PC, e.g TERMITE, REAL TERMINAL and Advanced Serial Port Terminal, the DATA bytes received or sniffed at the connected RS485 serial ports are NOT visible, or readable in HEX or ASCII, since the MCU starts to dump the data after power up (e.g. ASCII syntax to scan connected sensors at the SENSOR INTERFACE SERIAL PORTs).

Pictures and the USER MANUAL are attached for reference only.

Any help regarding this issue shall be appreciated.

Best Regards,

 

[barry]

I’m not sure I follow anything you’re saying, other than that you’ve got two devices with different baud rates connected. I think you need to resolve the baud rate issue before you do anything else.

 

[KlausST]

Hi,

the raw data sent via terminal software may not be human readable.
In so far I´m not sure what you report as an error .. really is an error.

All the data recived ... and translated into ASCII strings (repersenting a HEX value) are huma readable. No matter whether the data make sense or not.

--> thus I recommend to dive deeper into error investigation:
* what reply data length do you expect?
* what reply data length do you get?
* do you get any framing errors, parity error, stop bit error?

Do you have a scope to show the communication signals?

Klaus