Re: Building screen and keyboard RAM

Posted by rleininger on
URL: http://nand2tetris-questions-and-answers-forum.52.s1.nabble.com/Building-screen-and-keyboard-RAM-tp4032345p4036559.html

If you are asking about the interrupt mechanism of the Hack computer - there is none.  The Hack computer does not provide any kind of "hardware" interrupts.  The means by which the scan code of an attached hardware keyboard is provided to the Hack computer's keyboard register is hidden within the code that is used to implement the Hardware simulator and the CPU simulator programs.

Nothing in the hardware specification for the Hack computer, such as it is, provides a description of how the screen and keyboard interfaces work beyond the boundary of memory.  Only the effects seen on the screen based on current memory values and the value seen in the keyboard register based on the key depressed are described.