• Marcelo

    Marcelo - 2007-05-03

    What MCU is?

    • Maarten Brock

      Maarten Brock - 2007-05-03

      Not every question needs a new thread...

      MCU: MicroController Unit
      SDCC-DBG: What is that? We did not write that.
      Debug: Use --debug (that is two dashes).
      8 bits: 80's processors? Is that processors from 198x? Or is that 8048/8031/8051/8052 and alike? The short answer is only the mentioned processors and their derivatives.
      Retargettable: With quite some effort you can add support for other (8 bit) microcontrollers.


    • Marcelo

      Marcelo - 2007-05-04

      Thanks and sorry for many desnecessary threads.

      And sorry for disturbing!

      I meant procs from 1980s

      Other questions:

      (1) ADD A,04h

      I know this line means adding, by direct addressing, the value in register R4 to the Accumulator. But how to represent a number with only one bit of 04h?

      (2) Programming 8051 ports means to assign bits 0 or 1 to addresses 80h through FFh. In desktop PCs, we program ports by sending 1 or 8 bits f.e. to a device through out a bus. The question is: are not there buses in 8051 microcontrollers because of the obvious space matters, so the bits are sent to this internal memo area then the timer (watch dog) frequently checks their values to perform some I/O operation, f.e.?

      (3) What does it mean an I/O port to be high or low?

      (4) In Immediate Addressing:

      MOV A,#20h

      Can I only assign values to A in hexa format?

      (5) Are microcontrollers a kind of SoC??

      (6) I realized that as long as C is not Object Oriented nor has specific architecture constructions nor is verbose it is adequated to be portable for different systems programming. Right?

    • Maarten Brock

      Maarten Brock - 2007-05-04

      Re 1,2,3,4: I suggest to have a look at the Tutorial and FAQ's at and also at the so-called bible for 8051 there. Furthermore look in the datasheet of the microcontroller you intend to use.

      Re 5: That is one way to look at them.

      Re 6: Object Orientation has nothing to do with portability.


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