4.2.1 Interrupt Enable Flag ...........................................................................................................493
4.2.2 Interrupt Request Bit ............................................................................................................ 493
4.2.3 Changing the Interrupt Control Register .............................................................................. 494
4.2.4 Interrupt Priority Level Select Bit and Processor Interrupt Priority Level (IPL) .................... 495
4.3 Interrupt Sequence ..................................................................................................................... 496
4.3.1 Interrupt Response Time .....................................................................................................496
4.3.2 Variation of IPL when Interrupt Request is Accepted .......................................................... 497
4.3.3 Saving Registers ..................................................................................................................498
4.4 Returning from an Interrupt Routine ........................................................................................... 500
4.5 Interrupt Priority .......................................................................................................................... 500
4.6 Multiple Interrupts .......................................................................................................................502
4.7 Precautions for Interrupts ...........................................................................................................504
Chapter 5 External Buses __________________________________
5.1 Overview of External Buses ........................................................................................................ 508
5.2 Data Access ................................................................................................................................509
5.2.1 Data Bus Width .................................................................................................................... 509
5.2.2 Chip Selects and Address Bus ............................................................................................ 510
5.2.3 Bus Types ........................................................................................................................... 511
5.2.4 R/W Modes .........................................................................................................................511
5.3 Memory Space Expansion Features ........................................................................................... 512
5.3.1 Normal Mode ....................................................................................................................... 513
5.3.2 Memory Space Expansion Mode 1 ...................................................................................... 514
5.3.3 Memory Space Expansion Mode 2 ..................................................................................... 515
5.4 Connection Examples .................................................................................................................521
5.4.1 16-bit Memory to 16-bit Width Data Bus Connection Example ............................................ 521
5.4.2 8-bit Memory to 16-bit Width Data Bus Connection Example .............................................. 522
5.4.3 8-bit Memory to 8-bit Width Data Bus Connection Example ............................................... 524
5.4.4 Two 8-bit and 16-Bit Memory to 16-Bit Width Data Bus Connection Example .................... 525
5.4.5 16-bit Width Data Bus Connection Example in Memory Space Expansion Mode 1 ............ 526
5.4.6 8-bit Width Data Bus Connection Example in Memory Space Expansion Mode 1 ............. 527
5.4.7 8-bit Width Data Bus Connection Example in Memory Space Expansion Mode 2 ............. 528
5.4.8 Chip Selects and Address Bus ............................................................................................ 529
5.5 Connectable Memories ............................................................................................................... 530
5.5.1 Operation Frequency and Access Time .............................................................................. 530
RENESAS [ RENESAS TECHNOLOGY CORP ]
