ASM help

[Charles Linquis]

Darrel,

Thanks a million! While I don't know for sure, I'd guess that your little program is the start of something that will be really useful to all those people who post "how can I receive bytes while....... with my 16Fxxx". Tomorrow, I'll work on the SEND side and the buffering.

[Darrel Taylor]

Sure, no problem Charles,

Tomorrow, I'll work on the SEND side ...

Already done ...

Tmr_tx-18
http://www.picbasic.co.uk/forum/show...1&postcount=28

Or, at least it's a good start.
<br>

[Mike, K8LH]

Charles,

Just for an additional example and reference, I posted a 9600 baud half-duplex example on PICLIST several years ago that uses Timer 2 and IOC. I also have a full-duplex demo and another half-duplex demo that uses Timer 0 that shows how to reload a free-running 8 bit timer.

Hope the examples help. Have a great day.

Regards, Mike

;******************************************************************
;*                                                                *
;*  Filename: 12F683 Half-Duplex 9600 Demo.asm                    *
;*    Author: Mike McLaren, K8LH   (k8lh_at_arrl.net)             *
;*      Date: 02-Jun-05  (last revision 02-Dec-05)                *
;*                                                                *
;*   Half Duplex Bit-Banged 9600 Baud Serial I/O Demo             *
;*   (with 16-byte circular receive character buffer)             *
;*                                                                *
;*  ·Uses 12F683 INTOSC running at 8-MHz                          *
;*  ·Bit rate error 0.16% plus or minus 1.0% for INTOSC           *
;*  ·Bit-banged 9600 baud serial I/O                              *
;*    ·Half Duplex (should not TX and RX simultaneously)          *
;*    ·TMR2 interrupts at 104-usec intervals (every 208           *
;*     instruction cycles) and IOC (interrupt on change)          *
;*     for RX start bit leading edge detection on RXPIN           *
;*    ·Circular 16-byte RX character buffer                       *
;*    ·Inverted TX and RX signals (MAX232A or similar             *
;*     inverting RS-232 interface required)                       *
;*  ·Relatively small - the ISR and the support routines          *
;*   Init232, Put232, and Get232 use 102 words of code            *
;*   space at locations 0004 through 0069                         *
;*  ·Worst case 23% ISR 'overhead' (24-usecs) when a              *
;*   complete RX character is added to the circular               *
;*   buffer once every 1.04-msecs while receiving                 *
;*                                                                *
;*     MPLab: 7.21    (tabs=8)                                    *
;*     MPAsm: 4.02                                                *
;*                                                                *
;******************************************************************

[Darrel Taylor]

That is by far, the smallest program I've ever seen.
<br>

[Mike, K8LH]

Yeah, that didn't quite work out right Darrel (LOL). I'll go back and add the file...

Regards, Mike

Oops! Too late. I'll add it here (below). Sorry Gentlemen.

[Charles Linquis]

Thanks Mike,

I thought that I was the first guy who dreamed up (what I think is) a relatively elegant way to save processor cycles. I should have known better!

[Mike, K8LH]

Thanks Mike,

I thought that I was the first guy who dreamed up (what I think is) a relatively elegant way to save processor cycles. I should have known better!

You're welcome Sir. And btw, just about everything I ever ended up patting myself on the back for inventing seems to have been done before too (LOL)...

Regards, Mike