help for 89c51

Replies

• 

  maheshkrishnan

  Hi Vidya,
  Did you checked the Xtal connections given correctlly with correct value with ranges from "10 - 13 Mhz"
  Then If you are using 8051 it having internal Rom so no need for using external memory, you should be making the "EA" pin number i hope it is 31 for the 8051 make it to HIGH or (VCC).
  Then I am sure you will get the output with out any problem.
  then comeback with good projects.
  
  Thanks,
  mahesh krishnan
• 

  RachaelP

  Hi Vidya,
  
  What port are you looking at when trying to get it to output? If you are trying to output on Port 0 then its a little bit odd in that '0' drives low but write '1' it is floating and/or high-Z input. So basically you need to add external pull-ups on Port 0 pins that are being used as outputs.
  
  Hope this helps,
  
  Rach
• 

  hemant

  this is good solution i need another one if you able to get
  i m interfacing gsm modem to my microcontroller.i need to send sms
  through it.
  i am using AT commands for that.the command to send sms (AT+ CMGS)
  terminates with
  ctrl-Z.now in my program i hav tried all ways to send ctrl-Z at end of
  my sms.but it takes this as
  a character or string only.also i tried with ascii value of ctrl-Z but
  of no use.
  
  i am able to see the transmitted commands on hyper-terminal through
  serial interface & also on serail window while debugging.
  the commands are as follows with 2ms delay between each of them.
  
  AT ,, AT+CMGS = mobile no. , "message to be sent " ctrl-Z it is for the only end of statement