Rs485 Using Hserin/hserout

[koossa]

Could this happen when the 2 pics are on seperate power supplies?

[skimask]

Could this happen when the 2 pics are on seperate power supplies?

Might have something to do with all of those pauses you've got sprinkled in the code. If the pauses don't line up right (the moon, saturn, mars, etc), one part of the project, either the master or the slave, misses a reception at one time or another, and/or gets caught in the middle of one or the other...basically a sync'ing issue.

[koossa]

Hi Skimask

Must I remove all the pauses?
I am working on 2400 Baud and want to give enough time to transmit the data.

Thank you
Koossa

[skimask]

Hi Skimask
Must I remove all the pauses?
I am working on 2400 Baud and want to give enough time to transmit the data.
Thank you
Koossa

That's just it, you're giving it enough time to TX the data, but in the process of Pausing for 100ms afterwards, you might've missed 200-ish bits of serial data. The receive buffer is only 2 bytes deep (1 if you want be conservative). I'd say pause for 1 byte time, 4ms (2400 baud = .416ms/bit = 4.16ms/byte) instead of 100ms.

The SERIN and SEROUT commands won't let the program continue until they're finished transmitting or receiving.
HSERIN/HSEROUT, not sure about them, as I generally access the serial port registers directly rather than using the commands.
I would assume that they would act the same as SERIN and SEROUT for continuity purposes, but, I would hope that they would be 'non-blocking' commands (unless WAIT is used with HSERIN of course).

[koossa]

Don't know if I understand you correctly, but here is my new code

MASTER PIC
<HR>
<p>&nbsp;&nbsp; Include &quot;Modedefs.bas&quot;&nbsp;&nbsp;
&nbsp;&nbsp;
&nbsp;&nbsp; DEFINE OSC 4&nbsp;&nbsp;
&nbsp;&nbsp;
&nbsp;&nbsp; DE_OR_RE&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp; VAR&nbsp;&nbsp;&nbsp;&nbsp; PORTC.5&nbsp;&nbsp;&nbsp;&nbsp; ' DE and RE Pin of SN75176&nbsp;&nbsp;
&nbsp;&nbsp; RS232_DEBUG_PIN&nbsp;&nbsp;&nbsp;&nbsp; VAR&nbsp;&nbsp;&nbsp;&nbsp; PORTB.5&nbsp;&nbsp;&nbsp;&nbsp; ' Debugging to PC
&nbsp;&nbsp; LEDPIN&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n bsp;&nbsp; VAR&nbsp;&nbsp;&nbsp;&nbsp; PORTD.2&nbsp;&nbsp;&nbsp;&nbsp;' LED to confirm PIC is running&nbsp;&nbsp;
&nbsp;&nbsp; DATARECEIVED&nbsp;&nbsp;&nbsp;&nbsp; VAR&nbsp;&nbsp;&nbsp;&nbsp; BYTE&nbsp;&nbsp;
&nbsp;&nbsp;
&nbsp;&nbsp; '======== HSEROUT, HSERIN SETTINGS ========== &nbsp;&nbsp;
&nbsp;&nbsp; DEFINE&nbsp;&nbsp;&nbsp;&nbsp; HSER_RCSTA&nbsp;&nbsp;&nbsp; 90h&nbsp;&nbsp;
&nbsp;&nbsp; define&nbsp;&nbsp;&nbsp;&nbsp; HSER_TXSTA&nbsp;&nbsp;&nbsp; 20h&nbsp;&nbsp;
&nbsp;&nbsp; define&nbsp;&nbsp;&nbsp;&nbsp; HSER_SPBRG&nbsp;&nbsp;&nbsp; 103&nbsp;&nbsp;
&nbsp;&nbsp; DEFINE&nbsp;&nbsp;&nbsp;&nbsp; HSER_CLOERR&nbsp;&nbsp;&nbsp; 1&nbsp;&nbsp;
&nbsp;&nbsp; RCIF&nbsp;&nbsp;&nbsp;&nbsp; VAR&nbsp;&nbsp;&nbsp;&nbsp; PIR1.5&nbsp;&nbsp;
&nbsp;&nbsp; TXIF&nbsp;&nbsp;&nbsp;&nbsp; VAR&nbsp;&nbsp;&nbsp;&nbsp; PIR1.4&nbsp;&nbsp;
&nbsp;&nbsp;
&nbsp;&nbsp; ADCON1 = 7&nbsp;&nbsp;
&nbsp;&nbsp; TRISC = %10000000&nbsp;&nbsp;
&nbsp;&nbsp;
Main:&nbsp;&nbsp;
&nbsp;&nbsp; HIGH LEDPIN ' Indicate PIC is running&nbsp;&nbsp;
&nbsp;&nbsp; HIGH DE_OR_RE ' Make ready for TX&nbsp;&nbsp;
&nbsp;&nbsp; PAUSE 4&nbsp;&nbsp;
&nbsp;&nbsp; HSEROUT [&quot;S0&quot;] ' Send &quot;S0&quot;&nbsp;&nbsp;
&nbsp;&nbsp; LOW LEDPIN&nbsp;&nbsp;
&nbsp;&nbsp; LOW DE_OR_RE ' Make ready for RX&nbsp;&nbsp;
&nbsp;&nbsp; PAUSE 4&nbsp;&nbsp;
&nbsp;&nbsp; SEROUT RS232_DEBUG_PIN,N2400,[&quot;WAITING FOR REPLY..&quot;, 13, 10] ' DEBUG TO PC&nbsp;&nbsp;
&nbsp;&nbsp; if RCIF then&nbsp;&nbsp;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; hserin 100,Main,[WAIT (&quot;R&quot,DATARECEIVED]&nbsp;&nbsp;
&nbsp;&nbsp; ENDIF&nbsp;&nbsp;
&nbsp;&nbsp; SEROUT RS232_DEBUG_PIN,N2400,[&quot;REC:&quot;,DATARECEIVED, 13, 10] 'DEBUG TO PC&nbsp;&nbsp;
&nbsp;&nbsp;
&nbsp;&nbsp; GOTO Main&nbsp;&nbsp;
&nbsp;&nbsp;
END</p>

<HR>




SLAVE PIC
<hr>
<p>&nbsp;&nbsp; Include &quot;Modedefs.bas&quot;&nbsp;&nbsp;
&nbsp;&nbsp;
&nbsp;&nbsp; DEFINE OSC 4&nbsp;&nbsp;
&nbsp;&nbsp;
&nbsp;&nbsp; DE_OR_RE&nbsp;&nbsp;&nbsp;&nbsp; VAR&nbsp;&nbsp;&nbsp;&nbsp; PORTC.5&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ' DE and RE Pin of SN75176&nbsp;&nbsp;
&nbsp;&nbsp; LEDPIN&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n bsp; VAR&nbsp;&nbsp;&nbsp;&nbsp; PORTD.2&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ' LED to confirm PIC is running&nbsp;&nbsp;
&nbsp;&nbsp; DATARECEIVED&nbsp; VAR&nbsp;&nbsp;&nbsp;&nbsp; BYTE&nbsp;&nbsp;
&nbsp;&nbsp;
&nbsp;&nbsp; '======== HSEROUT, HSERIN SETTINGS ==========&nbsp;&nbsp;
&nbsp;&nbsp; DEFINE HSER_RCSTA 90h&nbsp;&nbsp;
&nbsp;&nbsp; define HSER_TXSTA 20h&nbsp;&nbsp;
&nbsp;&nbsp; define HSER_SPBRG 103&nbsp;&nbsp;
&nbsp;&nbsp; DEFINE HSER_CLOERR 1&nbsp;&nbsp;
&nbsp;&nbsp; RCIF VAR PIR1.5&nbsp;&nbsp;
&nbsp;&nbsp; TXIF VAR PIR1.4&nbsp;&nbsp;
&nbsp;&nbsp;
&nbsp;&nbsp; ADCON1 = 7&nbsp;&nbsp;
&nbsp;&nbsp; TRISC = %10000000&nbsp;&nbsp;
&nbsp;&nbsp;
Main:&nbsp;&nbsp;
&nbsp;&nbsp;
&nbsp;&nbsp; HIGH LEDPIN ' Indicate PIC is running&nbsp;&nbsp;
&nbsp;&nbsp; LOW DE_OR_RE ' Make ready for RX&nbsp;&nbsp;
&nbsp;&nbsp; PAUSE 4 &nbsp;&nbsp;
&nbsp;&nbsp; LOW LEDPIN&nbsp;&nbsp;
&nbsp;&nbsp; if RCIF then&nbsp;&nbsp;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; hserin 100,Main,[WAIT (&quot;S&quot,DATARECEIVED] ' Looking for &quot;S0&quot;&nbsp;&nbsp;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; IF DATARECEIVED = &quot;0&quot; THEN&nbsp;&nbsp;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n bsp; HIGH DE_OR_RE ' Make ready for RX&nbsp;&nbsp;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n bsp; PAUSE 4&nbsp;&nbsp;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n bsp; HSEROUT [&quot;R1&quot;] ' Send R1
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ENDIF&nbsp;&nbsp;
&nbsp;&nbsp; endif&nbsp;&nbsp;
&nbsp;&nbsp; GOTO MAIN&nbsp;&nbsp;
&nbsp;&nbsp;
END</p>
<hr>


As soon as I connect the Master pic to the power I get the following, does not matter if the Slave pic is running or not, it return the same data.

<b>
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
REC:ÿ
WAITING FOR REPLY..
</b>

Thank you
Koossa

[skimask]

I think you've got the idea...but one other thing I just thought about...

You're checking RCIF in the code. If you're checking RCIF, that means there's already a byte in the receive buffer. HSERIN probably waits for the next byte to come along (basically ignoring what's already in the buffer). If you're already WAITing for a specific character, then why also wait for a flag in hardware? Also, you can make use of the TIMEOUT in the SERIN/HSERIN to keep your code from getting stuck.

[koossa]

Thank you, I will remove the RCIF and see what happens.

There is a 100ms Timeout in my code.

Koossa