ch12-interrupts-interfaces

ch12-interrupts-interfaces - Interrupts and Interfaces...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Interrupts and Interfaces — 82C55 (parallel), 16550 (serial) EE 3750 figure from Brey 2 82C55 and interrupts Recall: In Modes 1 and 2, Port C contains interrupt request pins. Group A - PC3 (in Mode 1 in or out, also Mode 2) Group B - PC0 (in Mode 1 in or out)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
figure from Brey 3 Enabling 82C55 interrupts Must enable interrupts Group A input - program internal bit via PC4 Group A output - program internal bit via PC6 Group B - program internal bit via PC2 Example: Enabling input interrupts for Group A MOV AL, 1001B OUT CMD, AL 4 16550 and interrupts Can issue interrupts when transmitter ready to send another character receiver has received a character an error is detected while receiving data a modem interrupt occurs Recall: can set receiver trigger level
Background image of page 2
figure from Brey 5 Interrupt control, identification Interrupt control (enable) register — address ends 001 Interrupt identification register — address ends 010 if have multiple interrupts enabled, then check this register to determine
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 4

ch12-interrupts-interfaces - Interrupts and Interfaces...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online