16f88 ausart & defines

[cncmachineguy]

What about this:

Do the defines and set it up for pairity. This will make PBP do the math for it.
Then set the registers to 8 bit before HSEROUT and set them back when done.

[HenrikOlsson]

Now THAT is a good idea! I'll have to play with that in particular application and see how it works.

Thanks!

/Henrik.

[retepsnikrep]

Agreed that is a good idea. can you post your code example when tested.
I'll do the same If i get round to it first

OK so assuming i set up HSERIN/OUT for 9 bit even parity

I do my 9 bit recieve then just before I want to do my 8bit transmit i clear the TXSTA TX9 flag

Just a thought though if we clear the TXSTA TX9 flag just before we do the HSEROUt won't it just overwrite it immediately?

Is the TXSTA only loaded once during program execution when the define is executed? I appreciate the parity bit is changed to suit.

Or am I confused.

[cncmachineguy]

Hmmm, good point. I was/am assuming PBP sets and forgets it. setting it on each transmission seems like wasted code.

[retepsnikrep]

I'm going to try

DEFINE HSER_BAUD 9600		'Set Baud rate to 9600bps
DEFINE HSER_BITS 9		'Set to 9 bit mode
DEFINE HSER_EVEN 1		'Set Even Parity
DEFINE HSER_CLROERR 1 		'Clear overflow error automatically

TXSTA.6 = 0				'Clear 9 Bit Txd Mode

See if that works as clearing the 9 bit mode bit for the txd should hopefully
leave the rxd unaffected and in 9 bit mode.

Perhaps we can ask the pbpro author to support seperate defines for rxd and txd ausart.

[retepsnikrep]

This seem to work OK!

So I am receiving my 9600,8,E,1 data on Usart RXD Hserin

and

I am driving my lcd display using Usart TXD at 9600,8,N,1 Hserout

Defines as above in my previous post for parity

I just cleared the 9 bit register TXSTA.6 once at start of program after defines and seems to work fine!!

Thanks for all the ideas.

[HenrikOlsson]

Hi,
I've just tried this at my end and it seems to work fine. The DEFINE sets the RCSTA and TXSTA (once) as well as "tells" the compiler to insert code to calculate the parity bit for each byte it send and receives. If we then "override" and disables the transmision of the 9th bit PBP will still calculate and load that bit into the 9th databit "slot" but it will never get sent out.

In my particular case I'm swiching between using and not using parity for both RX and TX, at runtime, so I had to add dual HSERIN commands in my receive ISR, like:

If RCSTA.6 = 1 THEN              'If 9th bit reception is enabled we're using parity.
  HSERIN ParityError, [RxChar]
ELSE
  HSERIN [RxChar]
ENDIF
 
Goto OverParityError
 
ParityError:
'Handle it here
 
OverParityError:
'Continue here....

Thanks again for pointing this, now pretty obvious, way out!

/Henrik.

[HenrikOlsson]

Ha, talk about coincidence, posting pretty much the same thing at the same time like that. I didn't see your post before writing mine. It's great that you got it working at your end as well!

/Henrik.