a compiling error when declare secondary UART port

[naughty_mark]

Hi, all
I am new to Microchip, and I am using MPLAB v8.83 with CCS compiler PCD v4.133. I want to use two UART ports in my project, however, when I declare the second one, the compiler shows a error "Error 100 "main.c" Line 24(239,255): USE parameter value is out of range "UART2A" "

My code is

[Ttelmah]

Get rid of the pin definitions in the #use RS232.
Use #pin select to specify the pins before the #use RS232.

#USE RS232, does not reliably know about pin remapping. Generally, you must use pin select, to specify what pins the UART goes to, and then just tell #use RS232 to talk to UARTx.

However, that doesn't normally give the fault described - the pins just don't work (haven't got the compiler in front of me at present), It is possible there might be an error in the device database, and the compiler doesn't know the chip has four UART's. It is a relatively recent arrival in the database, and as such likely to have problems. If you have the IDE, run the device editor, and see if it shows the UART's.

I'd get rid of the '1A', and '2A' names for the UART's. These are normally reserved for chips that have the UART's available on two sets of pins, with 'UART1' selecting the UART on it's standard pins, and 'UART1A', using the alternate pins. This is not how your chip works, with the UART re-mappable to any one of dozens of pins. The 'A' nomenclature may not therefore be understood. So, just use UART1, UART2 etc., and map the pins first. Also in general with re-mappable peripherals, make sure you set the TRIS on the pins, the compiler tends to not get this right....

Best Wishes

[FvM]

[naughty_mark]

Thank you FvM and Ttelmah, your suggestions are really helpful!

To Ttelmah, I tried to add "#pin_select" before using "#use rs232", it works! at least passed the compile ( I will test if it can really work later ).
After I used "#pin_select" to assign pins to UART2, then I can use "UART2" in "#use rs232" but "UART2A" doesn't work.
And if I didn't use "#pin_select" for UART1 like the code I posted in first poster, I can only use "UART1A" but not "UART1". And if I use "#pin_select" for UART1 and then use "#use rs232", then both "UART1" and "UART1A" work!!
I really got confused on definition between UARTX and UARTXA, as compiler manual says, UARTX means using the dedicated pin and UARTXA means using re-mappable pin, however in dsPIC33EP512MU814, there is no dedicated pins for any UART ports.

Anyway, now it can be compiled and I hope it will work fine. If you can answer my question above to let me get clear view of this function, I do appreciate. Thanks for your guys help.

Regards

[Ttelmah]

Yes, it is poorly documented, and confusing.
Basically, it works like this:

1) Using the name UARTx, says 'talk to this set of UART hardware, and assume the default pins'.
2) Using UARTxA, says talk to this set of UART hardware, and map the pins to their alternate address. This only really works with chips that have just two sets of UART pins. It gets worse, because CCS's selection of which is primary, and which is the 'alternate', does not always agree with the data sheet.
You say:
"as compiler manual says, UARTX means using the dedicated pin and UARTXA means using re-mappable pin". This is not what my manual says. It says:
"UART1 Sets the XMIT= and RCV= to the chips first hardware UART.
UART1A Uses alternate UART pins"
Note the use of the word 'alternate', _not_ re-mappable. Quite a few of the chips that appeared before re-mapping became the norm, have two sets of UART pins, referred to as 'primary', and 'alternate'. This is what this for is for.
3) #PIN_SELECT, allows you to assign particular re-mappable hardware peripherals to particular pins.

If you treat the two operations as separate, it seems to work the best:
1) Map the pins you want to the peripheral you want.
2) Then setup the peripheral, and just say 'use the default hardware'.
This way the compiler doesn't try to do too much, and doesn't get (too) confused, and works.

In some senses, part of the problem is CCS trying to be a little 'too smart'. Hiding things like selecting the alternate pins 'inside' the RS232 setup, and then not being able to cope as features get yet more complex.
It is a pity that they didn't separate these at the early stages, just have #use RS232, with UART1, to select the hardware UART, and then a separate line saying 'SELECT_ALTERNATE_UART_PINS', and the #PIN SELECT for chips with more complex re-mappping. Keeping the mapping 'distinct' from the #USE RS232. Currently you have the strange situation with #USE RS232 able to cope with selecting the alternate pins, but not with re-mappable pins.....

Best Wishes