trux@atop.atop.cs.caltech (Flem Snopes) (04/07/91)
I want to use the acknowledge line on my paralell port to trigger interrupt 0Fh. I enable IRQ7 on the 8259 PIC, then I hook interrupt 0Fh. When I bring ACK low, the interrupt happens but when I bring ACK low again (after it going high for some time) the interrupt is not triggered. Is there some flag I need to set to let the 8259 Programmable Interrupt Controller know I am ready to deal with the next -ACK signal? Thanks. -trux -- **************************************************************** * Flem Snopes * * Dabney 1-58 " From childhood's hour I have not been * * Caltech As others were--I have not seen * * Pasadena, CA As others saw--I could not bring * * 91126 My passions from a common spring-- " * * 818-564-8011 * ****************************************************************
np4@prism.gatech.EDU (POMPONIO,NICHOLAS A) (04/13/91)
trux@atop.atop.cs.caltech (Flem Snopes) writes: >I want to use the acknowledge line on my paralell port to trigger interrupt >0Fh. I enable IRQ7 on the 8259 PIC, then I hook interrupt 0Fh. When I bring >ACK low, the interrupt happens but when I bring ACK low again (after it going >high for some time) the interrupt is not triggered. Is there some flag I need >to set to let the 8259 Programmable Interrupt Controller know I am ready to >deal with the next -ACK signal? Thanks. >-trux Try issuing a "non-specific EOI" by writing 20H to I/O port 20H. This is generally done within the interrupt service routine. -- POMPONIO,NICHOLAS A Georgia Institute of Technology, Atlanta Georgia, 30332 uucp: ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!np4 Internet: np4@prism.gatech.edu