How to receive numbers from Keil C51 to PIC16F628 in CCS?

[GrandAlf]

I am wanting to send numbers 0-255 from k*e*il c51 to PIC16F628 programmed with CC*S C. It seems that I can send them with printf %U, but I am not sure about how to receive them. If I use any of the built in commands, such as getc, it appears to interpret them as characters rather than numbers. Supposing I send 13, it would be interpreted as CR by getc rather than 13. which is what I require. I just need to to receive the number, but not echo it. Any advice appreciated.

 

[C-Man]

how to enable serial port ccs

Check out the CCS forum at:

https://www.ccsinfo.com/forum

You will get a lot of ideas just browsing their forum ...

The guys there are nearly as nice as the members here

best regards

 

[GrandAlf]

ccs getc

Thanks C-Man,

Got some useful stuff there. Another question if I may, Anyone know how to use the serial port on Atmel 89S8252 with K*eil C51. I know it is referred to as TXD in the header file. Dont seem to be able to find info on setting baud rates etc. Xtal is 12mhz, and I need to sed the baud rate to 300. Also I assume that when using printf %u, I need to specify the stream as TXD ?. Sill learnig C, any help appreciated.

PS, Only need to transmit without handshaking.

 

[GrandAlf]

ccs serial getch

Just another thought. As I only want to output a single 8 bit number at any one time, can I just use the statement SBUF = oxxx;. I guess I need to set up the timers for the baud rate, not sure how to work it out. Also I am using tiny RTOS, will this cause serial probs?. Sorry! lots of questions.

 

[C-Man]

getch vs getc ccs

This is a short snippet out of one of my C51 programs to initialize communication:

/* RS232 Init at 19200 Baud (using Timer1) */
TH1=0xFD; /* 19200 baud @ 11.0592MHz*/
TL1=0xFD;
SCON=0x50; /* 01011010b: UART Mode1, enable receiver */
PCON=SMOD_; /* double baudrate '/
TR1=1; /* start timer 1*/
ES=1; /* Serial Interrupt on */

If you use interrupt driven RS232 there should not be a problem with RTOS but I have not used RTOS so I can not tell you for sure ...

hope this helps

 

[GrandAlf]

ccs baudrate

This is great C-Man, How do you work out the baud rate values?, need to use 300 with 12mhz xtal (system clock 1Mhz). Going to try and download atmel data sheet to see if I can find the info, don't expect you to do all the work!. BTW, can you use SBUF like above, seems to compile OK, but unable to test as yet.

 

[C-Man]

ccs serial interrupt

Maybe Mr. Keil can help you

hxxp://www.keil.com/c51/baudrate.asp

And yes just use SBUF to get/put from/to 8051 USART but you have to check the USART flags if you are allowed to get/put a new byte from/to USART.

I am afraid the title of this topic is a little off now ...

best regards

 

[GrandAlf]

ccs c getc()

Is getting rather off topic I think, anyway managed to find the solution.

void serial_init (void) {
SCON = 0x50; // mode 1: 8-bit UART, enable receiver
TMOD |= 0x20; // timer 1 mode 2: 8-Bit reload
TH1 = 0x98; // reload value 300 baud
TR1 = 1; // timer 1 run
ES = 1; // enable serial port interrupt
}

thanks for your advice