80C186EB/80C188EB Microprocessor User's Manual - CEUNES

CONTENTS8.2.6 Edge and Level Triggering ......................................................................................8-108.2.7 Additional Latency and Response Time .................................................................8-108.3 PROGRAMMING THE INTERRUPT CONTROL UNIT ............................................... 8-118.3.1 Interrupt Control Registers ......................................................................................8-128.3.2 Interrupt Request Register ......................................................................................8-168.3.3 Interrupt Mask Register ...........................................................................................8-178.3.4 Priority Mask Register .............................................................................................8-188.3.5 In-Service Register .................................................................................................8-188.3.6 Poll and Poll Status Registers .................................................................................8-198.3.7 End-of-Interrupt (EOI) Register ...............................................................................8-218.3.8 Interrupt Status Register .........................................................................................8-228.3.9 Initializing the Interrupt Control Unit ........................................................................8-23CHAPTER 9TIMER/COUNTER UNIT9.1 FUNCTIONAL OVERVIEW............................................................................................ 9-19.2 PROGRAMMING THE TIMER/COUNTER UNIT .......................................................... 9-69.2.1 Initialization Sequence ............................................................................................9-119.2.2 Clock Sources .........................................................................................................9-129.2.3 Counting Modes ......................................................................................................9-129.2.3.1 Retriggering ...................................................................................................9-139.2.4 Pulsed and Variable Duty Cycle Output ..................................................................9-149.2.5 Enabling/Disabling Counters ...................................................................................9-159.2.6 Timer Interrupts .......................................................................................................9-169.2.7 Programming Considerations ..................................................................................9-169.3 TIMING ........................................................................................................................ 9-169.3.1 Input Setup and Hold Timings .................................................................................9-169.3.2 Synchronization and Maximum Frequency .............................................................9-179.3.2.1 Timer/Counter Unit Application Examples .....................................................9-179.3.3 Real-Time Clock .....................................................................................................9-179.3.4 Square-Wave Generator .........................................................................................9-179.3.5 Digital One-Shot ......................................................................................................9-17CHAPTER 10SERIAL COMMUNICATIONS UNIT10.1 INTRODUCTION ......................................................................................................... 10-110.1.1 Asynchronous Communications ..............................................................................10-110.1.1.1 RX Machine ...................................................................................................10-210.1.1.2 TX Machine ...................................................................................................10-410.1.1.3 Modes 1, 3 and 4 ...........................................................................................10-610.1.1.4 Mode 2 ..........................................................................................................10-710.1.2 Synchronous Communications ...............................................................................10-810.2 PROGRAMMING......................................................................................................... 10-910.2.1 Baud Rates ...........................................................................................................10-10vii