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Nevillestone
Joined: 05 Aug 2014 Posts: 24
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USE RS232 |
Posted: Fri Jul 26, 2019 1:34 am |
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HI
I'm using a serial port for a 485 bus and using USE RS232 built-in function.
It works however I'm having to control the enable bit manually back to receive mode after transmitting.
Is there a setting to set it to RX Mode as default ? I can't find anything in the manual.
Using
Code: | #USE RS232 (baud=1200,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8,stream=PORT1,enable=PIN_B2)
#define RS485_USE_EXT_INT TRUE |
Thanks
Neville _________________ Neville |
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dluu13
Joined: 28 Sep 2018 Posts: 395 Location: Toronto, ON
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Re: USE RS232 |
Posted: Fri Jul 26, 2019 3:31 am |
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Nevillestone wrote: | HI
I'm using a serial port for a 485 bus and using USE RS232 built-in function.
It works however I'm having to control the enable bit manually back to receive mode after transmitting.
Is there a setting to set it to RX Mode as default ? I can't find anything in the manual.
Using
Code: | #USE RS232 (baud=1200,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8,stream=PORT1,enable=PIN_B2)
#define RS485_USE_EXT_INT TRUE |
Thanks
Neville |
I know that the included modbus.c library will handle all that stuff automatically. There's also a rs485.c in the drivers folder, which I have never used. |
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temtronic
Joined: 01 Jul 2010 Posts: 9241 Location: Greensville,Ontario
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Posted: Fri Jul 26, 2019 4:32 am |
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I've always tied _RE and DE of the RS485 device together so that both pins were controlled as the 'ENABLE' pin in the USE RS232(....options...). Can't recall ever having a problem.
If you physically tie _RE low (to gnd), the RS485 receiver 1/2 will always be active, which means the PIC will see it's own transmitted data.
You need to cut a small program/compile and dump the listing to see what CCS does with the 'ENABLE' pin. I suspect it goes high, send data, goes low.
I'd do it but my manure spreader needs new beater bearings....
Jay |
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