How to use software UART?

[shardul]

I've been trying for a week to debug my software UART routine and have not succeeded yet.
It generates signal for hardware UART but not for pins which i define.
my code is

[Ttelmah]

You are using 'MULTI_MASTER', without defining a separate 'RETURN' pin. As such the RCV pin will be treated as the return pin (PIN B6), and the code _will not transmit, unless this is high_. I'd guess it is not high.
If this line is detected to not be high when you go to transmit, bit 6 of 'RS232_ERRORS' will be set, and _all_ future data output on the port will stop, till you clear this bit.

Best Wishes

[asmallri]

You have also specified Errors and force_sw. These are mutually exclusinve. Errors is used to tell the compiler to generate extra code to detect an error condition of the hardware UART and restart the hardware UART if the error condition exists.
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[Ttelmah]

ERRORS, is not mutually exclusive to FORCE_SW. When using hardware, it is 'required', but with a software UART, it still enables the RS232_ERRORS byte, with bit 7 of this giving the 9th data bit, and bit 6 the collision for multi_master, or float_high mode.

Best Wishes

[shardul]

Thanks a ton Ttelmah

i did that change and the pin started transmitting the signal
can you do one favour ... wil you tell me how these settings should be
i mean multi master and several other things like what might affect/required for transmission of software UART
it would be a BIG help cause i'm tryin to use 1HW+2SW UARTs

[Ttelmah]

Ouch. You really need to do a bit of research.
Seriously, look at the examples. Realise how _few_ settings they use. You have so many things that would not normally be used, that it is terrifying....

Bits=9 - do you really want this. 99.9% of serial communications, uses 7 or 8 data bits, not 9.
Long_data - only used if you are sending more than a byte at a time. Links to the above.
force_sw - not needed. Only wanted, if you are using the _hardware_ pins, and want to ensure a software UART is used, for things like multi-master operation.
Multi-master - not wanted/needed. Only wanted if you are using a half duplex bus on something like RS485, not 232, which allows different devices to 'control' the bus (be the master). Hence devices can't send, till 'they' have control of the bus.
Enable - only used again, if you are using half-duplex communications, and need a line to control the bus transceiver. Otherwise just wastes a pin....

Have you looked in the forum, about software RS232. Are you aware of the _limitations_ this imposes:

You can only do _one_ thing at a time. One channel receiving, or one channel transmitting. If your code needs comms on two 'non hardware' ports at the same time, you need to be using another solution (more complex software, or - better - hardware). The fact you refer to a 'sensor', suggests that this is a device that is going to want to send you data. As such, _problems_.

Search the forum.

Best Wishes

[shardul]

sorry .... but i'm a newbee to this
i'm using two RS232 & one RS485 and looking at ccs rs485 example i set bit to 9 ... else it was 8
I'll be sending a string over the line to detect a specific sensor (rs485) => does it justify "long data" & "multi master"
and i'm using enable pin (hardware connected to max13430)

I've read "#use rs232" in help section & constructed that code
just wasn't sure where things were going wrong.

Thanks again ...

[Ttelmah]

[asmboy]

let me give you a friendly tip:
sooner or later your your communication will fail with bad chars being received &&|| being dropped.

for two channels of SOLID data com - consider the 18f46K22 with TWO hardware uarts and set up #INT_RDA handlers for EACH.

then and only then will you have two channels you can TRUST to work.
the software uart is a sketchy bit of code at best and has ZERO reliability if there are ANY INTS enabled or if there is a hardware UART running at the same time or even if you are trying to do a "soft" RS232 outbyte at the same time. i would never let soft RS-232 loose on a customer that i ever expect to do biz with in the future.

[shardul]

yeah .... there'll be data sent by slaves to master

and thank u all for suggestions ..... i'll be careful & will do some homework before applying anythin