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For those wanting to do it with interrupts, download the Soft Uart for P12 by Warren Schroeder project from http://www.mikroe.com/en/projects/
It's an excellent tutorial as well as an interrupt driven full-duplex software UART. The code is quite simple and easy to follow.
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Hi,Originally Posted by dhouston
Full-duplex software UART is not possible or possible only if the baud rate
is very low and interrupts are used. (Software UARTs use bit-banging).
Soft Uart for P12 by Warren Schroeder:
If you look at the code you will see that RX uses an interrupt and that in
the SUB TX_19200 interrupts are disabled. This means that while
you are sending data you cannot receive data at the same time. (Not Full-duplex).
Best regards,
Luciano
Last edited by Luciano; - 9th January 2008 at 18:31.
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It could be done if you send and receive in the interrupt. Set it to interrupt at 2*baud, and alternate Tx/Rx. At 9600 baud, with 19200kHz interrupt rate on a 20MHz crystal, you get 260 code cycles to perform each...that should be more than enough, and cycles left over for other regular code. You might even get close to that rate with a 4MHz crystal if you are thrifty with your code.
Or, in the interrupt do the Tx send first, then all Rx work, then Tx setup for the next bit, without alternating, so the "Tx send" portion is actually very short and always the same length. This might be more efficient, but maybe a little more coding.
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MikroE Basic
Luciano -
I will try that code. The last time I tried the Soft_Uart_Read was blocking. I see v6.0.0.0 has a heap of changes.
I just found it frustrating when trying to convert a simple working PBP program to MikroE Basic. What better way to learn a new language than to convert code you already know and understand in PBP.
I'll stick with PBP for now until I need ethernet or have some time to do some test projects.....
bill.
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