Non-Invasive Control of a Processor-Based Board
Original Publication Date: 1988-Mar-01
Included in the Prior Art Database: 2005-Feb-14
A method for gaining control of a processor-based board is presented. To test the board, it is necessary to test the processor and then the other components on the board. The board can also be externally monitored and forced to do things that its own design and operating code would not allow. Previously, to gain control of a processor, the processor read- only memory (ROM) would have to be disabled, remapped or physically removed. In all cases, something on the processor board would be disabled and the board would not be fully functional. These types of methods are "invasive". For certain processors there is another method to gain control. In the specific case of the Intel 8088 processor, a better method is to drive certain address lines (A19-A16) to ground upon reset going inactive.