ISO1432: ISO1432 Half Duplex Communication Transmit data loss..

Ajay S

Part Number: ISO1432

Dear Team ,

Please find our Block diagram of our system. We facing issue when multiple slave of ISO1432 in half duplex...

In our system when HMI send request to two salves, only one slave able send and receive information to master (HMI). another slave able to receive request from master (HMI) but not transmit correct data..

we able to receive request in both slave but out of 2 anyone of slave is able transmit data .. the other one when we debug all data are correct placed in buffer , but while transmit when we see in serial analyzer its show,, data always zero..

for example 16 array..

working slave..

001 002 015 010 020 100 060 000 000 000 000 000 000 000 000 000 018

Problematic slave

000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000

Please note that while transmitting frame size matching in both slave.. but problematic slave data is zero zero..

we cant judge the slave which one working... suppose slave1 power on and slave two power on after sometime slave 1 working...

suppose slave2 power On frist and slave 1 power after sometime slave 2 working... Please find circuit below.

Thanks in advance fot your support and guidance

Rgds

Ajay S

over 4 years ago

0 Manuel Chavez over 4 years ago

TI__Genius 17100 points

Hi Ajay,

Thank you for posting to E2E! To confirm whether this is a problem regarding the isolator, can you please share oscilloscope waveforms of the RS-485 bus pins (A,B and Z,Y) with their respective digital signal (R, /RE and D, DE) respectively?

The configuration from the schematic also seems to be full duplex, not half-duplex. Can you confirm the connections are all made as expected in the hardware as well?

Respectfully,
Manuel Chavez

0 Ajay S over 4 years ago in reply to Manuel Chavez

Expert 1280 points

Hi.. Manuel,

We short jumper jp2 and jp5 for half duplex.. We share waveform shortly.

Regards

Ajay s

0 Manuel Chavez over 4 years ago in reply to Ajay S

TI__Genius 17100 points

Thanks for confirming this, Ajay.

I look forward to your response including the requested waveforms.

Thank you,
Manuel Chavez

0 Ajay S over 4 years ago in reply to Manuel Chavez

Expert 1280 points

Hi Manuel,

we figure out that our issue is related to below links software issue and confirmed while debugging array size mismatch while slave reply to master and another node also receive same so SCI_readCharArray gets struck .. we trying to rectify with respect below links , so i am closing this thread , thank you for your valuable time and support..

(+) TMS320F28388D: Interrupt on SCI-C Rx - C2000 microcontrollers forum - C2000︎ microcontrollers - TI E2E support forums

Thanks and Regards

Ajay S

Isolation

Isolation forum

ISO1432: ISO1432 Half Duplex Communication Transmit data loss..