1. Communicating With Devices Interrupts Lecture 10.4 Section 10.6

2. Communicating Between Devices Device makes a request to the CPU by bringing request line HIGH

3. Communicating Between Devices Processor takes the number provided by the encoder and uses it to switch MUX and deMUX

4. Communicating Between Devices Using this number, CPU acknowledges the communication and ‘conversation’ commences

5. Communicating Between Devices Processor accepts information on Input lines and sends information on Output lines

6. Communicating Between Devices Processor ends communication by bringing acknowledge line LOW. Device ends its request

7. Communicating Between Devices Processor ends communication by bringing acknowledge line LOW. Device ends its request

8. Communicating Between Devices

11. 68000 Interrupt Logic Peripheral 74148 Encoder 74138 Decoder IP0 IP1 IP2 A0 A1 A2 IRQA 68000 Data Bus IRQ

12. External Devices Interrupting a CPU

13. State Diagram for the Interrupt Handler

14. Interrupt Handler