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???
03/17/09 23:57
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 		 #163550 - Use Timer 2...
Responding to: ???'s previous message
Chico said:
Hello, I need an AT89S52 to receive serial data at 31.250 kbps and send serial data at 250 kbps.

I know how to make 31.250 kbps with 12mhz crystal, and know how to make 250 kbps with 16mhz crystal, but dont know how to make both at same time with just 1 crystal... how can I do this? it is possible?

Use Timer 2 in "baud rate generator" Mode:

At 8MHz clock speed set RCAP2H=255 and RCAP2L=248 for 31.25kBaud and set RCAP2H=255 and RCAP2L=255 for 250kBaud.

At 16MHz clock speed set RCAP2H=255 and RCAP2L=240 for 31.25kBaud and set RCAP2H=255 and RCAP2L=254 for 250kBaud.

Kai

List of 53 messages in thread
TopicAuthorDate
Is possible? AT89S52 with dual serial baud rate            01/01/70 00:00      
   yes...            01/01/70 00:00      
   Use Timer 2...            01/01/70 00:00      
      Can I have both at same time?            01/01/70 00:00      
         you can't have different baudrates...            01/01/70 00:00      
         YES            01/01/70 00:00      
         No, unless...            01/01/70 00:00      
            what registers?            01/01/70 00:00      
               Split-speed common in older times            01/01/70 00:00      
               Timer 2 registers of AT89S52            01/01/70 00:00      
   Where can I read...            01/01/70 00:00      
      Well, in the datasheet!            01/01/70 00:00      
      Tutorials; FAQs            01/01/70 00:00      
   You have two UART's ... Does that give you any ideas?            01/01/70 00:00      
   Timer2 baudrate            01/01/70 00:00      
      unconfuse yourself            01/01/70 00:00      
      What's wrong with page 15 of datasheet?            01/01/70 00:00      
      Trying this...            01/01/70 00:00      
         Have a look at this code example...            01/01/70 00:00      
            This damn 52 think it is a 51 !!!            01/01/70 00:00      
               counterfeit chip?            01/01/70 00:00      
   It is for a Midi to DMX project... new trouble            01/01/70 00:00      
      Alternatives            01/01/70 00:00      
         examples            01/01/70 00:00      
            Options            01/01/70 00:00      
   Found the crystal!            01/01/70 00:00      
      Let's see ... What is wanted here ...            01/01/70 00:00      
         He is already using two timers            01/01/70 00:00      
            Independent UARTs            01/01/70 00:00      
               Crystal seens OK - Could receive Midi.. "partially" send DMX            01/01/70 00:00      
                  Well done!            01/01/70 00:00      
                  Russel Bull... Can you please take a look in my code?            01/01/70 00:00      
                  I wouldn't use serial transmission interrupts            01/01/70 00:00      
                     Makes sense!            01/01/70 00:00      
                        Give this a try...            01/01/70 00:00      
                           Hard to find a place to test.            01/01/70 00:00      
                              Runtime of LCALL...            01/01/70 00:00      
                           stop bits            01/01/70 00:00      
                              TI flag is set at the begin of (first) stop bit!            01/01/70 00:00      
                                 TI/RI setting time            01/01/70 00:00      
                                    TI and RI details...            01/01/70 00:00      
   TI/RI question            01/01/70 00:00      
      what causes a serial int?            01/01/70 00:00      
      More things will happen...            01/01/70 00:00      
         If....            01/01/70 00:00      
            Yes            01/01/70 00:00      
   YEAAAAAAAAH! IT WORKED            01/01/70 00:00      
      Congrats!            01/01/70 00:00      
         Thanks really a lot!            01/01/70 00:00      
   A new challenge! The inverse way!            01/01/70 00:00      
      BREAK detection is lousy!            01/01/70 00:00      
         RB8            01/01/70 00:00      
            RB8 details...            01/01/70 00:00      

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