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???
05/08/08 17:03
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#154586 - Ah makes sense.....
Responding to: ???'s previous message
Here is the "hopefully" the final go round, I ran it through and it seems to do a very nice job. Original code size was 912 bytes, now reduced to 726 bytes. I have an ocean of space @ 16KB using the LPC936, but it makes for a more efficient and better coding technique and with the added bonus of learning a bit more.....thanks folks.
void RS232_Write(unsigned char reg, unsigned char dat0, unsigned char dat1)
{

unsigned char REG_H, REG_L, DAT1_H, DAT1_L, DAT2_H, DAT2_L, CHECKSUM_H,
			  CHECKSUM_L, CHECKSUM_T;

REG_H = Hex2Ascii(reg >> 4);	  // do the Upper Nibble
REG_L = Hex2Ascii(reg & 0x0F);	  // do the Lower Nibble

DAT1_H = Hex2Ascii(dat0 >> 4);	  // do the Upper Nibble
DAT1_L = Hex2Ascii(dat0 & 0x0F);  // do the Lower Nibble

DAT2_H = Hex2Ascii(dat1 >> 4);	  // do the Upper Nibble
DAT2_L = Hex2Ascii(dat1 & 0x0F);  // do the Lower Nibble

CHECKSUM_T = (cam_header + cam_ID_H + cam_ID_L + REG_H + REG_L + DAT1_H + 
			 DAT1_L + DAT2_H + DAT2_L);

CHECKSUM_H = Hex2Ascii(CHECKSUM_T >> 4);	// do the Upper Nibble
CHECKSUM_L = Hex2Ascii(CHECKSUM_T  & 0x0F);	// do the Lower Nibble

//***********************************************************************
uart_init();
uart_transmit(cam_header); 	Wait(2); 	// header
uart_transmit(cam_ID_H); 	Wait(2); 	// ID H
uart_transmit(cam_ID_L); 	Wait(2); 	// ID L
uart_transmit(REG_H); 		Wait(2); 	// Register H
uart_transmit(REG_L); 		Wait(2); 	// Register L
uart_transmit(DAT1_H); 		Wait(2);	// Data 1 H
uart_transmit(DAT1_L); 		Wait(2);	// Data 1 L
uart_transmit(DAT2_H); 		Wait(2);	// Data 2 H
uart_transmit(DAT2_L); 		Wait(2);	// Data 2 L
uart_transmit(CHECKSUM_H); 	Wait(2);	// Send calculated checksum 1
uart_transmit(CHECKSUM_L); 	Wait(2);	// Send calculated checksum 2
//***********************************************************************
}

unsigned char Hex2Ascii(unsigned char HexValue)
{
return "0123456789ABCDEF"[HexValue];
}


List of 35 messages in thread
TopicAuthorDate
Problem with the toascii() w/ clarification            01/01/70 00:00      
   toascii not what you want            01/01/70 00:00      
      Ah yes.....makes sense            01/01/70 00:00      
         C does know ASCII            01/01/70 00:00      
            the final result:            01/01/70 00:00      
               That is a LOT of code            01/01/70 00:00      
                  It won't compile in its state because...            01/01/70 00:00      
               Grossly inefficient!            01/01/70 00:00      
                  A small trick            01/01/70 00:00      
                     small trick is cool.....            01/01/70 00:00      
                        Same as Neil's            01/01/70 00:00      
                           Ah makes sense.....            01/01/70 00:00      
                              You can still do better            01/01/70 00:00      
                                 LOL....Russ.......LOL            01/01/70 00:00      
                                    sprintf()            01/01/70 00:00      
                                       I had you at <>            01/01/70 00:00      
                                          So why not sprintf()?            01/01/70 00:00      
                                             You are right......I did say that            01/01/70 00:00      
                        How the small trick works            01/01/70 00:00      
                           Is it worth it?            01/01/70 00:00      
                              Same assembly generated for me            01/01/70 00:00      
                           You said index.....click click....very nice            01/01/70 00:00      
                              fast (sic?) lookup table            01/01/70 00:00      
                                 Faster? Probably not.            01/01/70 00:00      
               What's in a name?            01/01/70 00:00      
                  true.....but at this point.......            01/01/70 00:00      
                     Tricks and treats            01/01/70 00:00      
                     there is no time lost by doing it right            01/01/70 00:00      
                        You guys are completely right,            01/01/70 00:00      
                           the very simple way to (almost) do it right            01/01/70 00:00      
                           For the sake of learning            01/01/70 00:00      
                              Good point            01/01/70 00:00      
   UART doesn't know ASCII            01/01/70 00:00      
      Good point....but            01/01/70 00:00      
   Unhelpful documentation            01/01/70 00:00      

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