i make a small program which includes initializing the baud rate, serial port1 control and what mode it would operate. I also include this: mov a, #33h mov scon1, a mov a, #00h mov a, scon1 when i run the simulation, #33h was put to the accumulator and it was transferred to sbuf1..and the accumulator was reset to 00h. However, it didn't get 33h from sbuf1 back to accumulator. and i wonder why???
However, it didn't get 33h from sbuf1 back to accumulator. and i wonder why??? Is there any particular reason you try to keep it secret what it read back? If you have a working ISR the port will read 30h back. btw. the mov a, #00h indicates that you need to read up on the basics of the '51. i suggest "the bible" Erik here are the links to "the bible" Chapter 1 http://www.semiconductors.philips.com/acrobat/various/80C51_FAM_ARCH_1.pdf chapter 2 http://www.semiconductors.philips.com/acrobat/various/80C51_FAM_PROG_GUIDE_1.pdf chapter 3 http://www.semiconductors.philips.com/acrobat/various/80C51_FAM_HARDWARE_1.pdf