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7721 Group User’s Manual
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Table of contents
Table of contents
CHAPTER 1 DESCRIPTION
1.1 Performance overview.......................................................................................................... 1-2
1.2 Pin configuration................................................................................................................... 1-3
1.3 Pin description ...................................................................................................................... 1-4
1.4 Block diagram........................................................................................................................ 1-7
CHAPTER 2 CENTRAL PROCESSING UNIT (CPU)
2.1 Central processing unit ....................................................................................................... 2-2
2.1.1 Accumulator (Acc) ......................................................................................................... 2-3
2.1.2 Index register X (X)....................................................................................................... 2-3
2.1.3 Index register Y (Y)....................................................................................................... 2-3
2.1.4 Stack pointer (S)............................................................................................................ 2-4
2.1.5 Program counter (PC) ................................................................................................... 2-5
2.1.6 Program bank register (PG) ......................................................................................... 2-5
2.1.7 Data bank register (DT)................................................................................................ 2-5
2.1.8 Direct page register (DPR)........................................................................................... 2-6
2.1.9 Processor status register (PS)..................................................................................... 2-7
2.2 Bus interface unit ................................................................................................................. 2-9
2.2.1 Overview ......................................................................................................................... 2-9
2.2.2 Functions of bus interface unit (BIU)........................................................................ 2-11
2.2.3 Operation of bus interface unit (BIU)........................................................................ 2-13
2.3 Access space....................................................................................................................... 2-15
2.3.1 Banks ............................................................................................................................ 2-16
2.3.2 Direct page ................................................................................................................... 2-16
2.4 Memory assignment ........................................................................................................... 2-17
2.4.1 Memory assignment in internal area......................................................................... 2-17
2.4.2 External area................................................................................................................ 2-18
2.5 Bus access right ................................................................................................................. 2-23
CHAPTER 3 CONNECTION WITH EXTERNAL DEVICES
3.1 Signals required for accessing external devices .......................................................... 3-2
3.1.1 Descriptions of signals.................................................................................................. 3-2
3.1.2 Operation of bus interface unit (BIU).......................................................................... 3-5
3.2 Software Wait......................................................................................................................... 3-8
3.3 Ready function .................................................................................................................... 3-10
3.3.1 Operation description .................................................................................................. 3-11
3.4 Hold function ....................................................................................................................... 3-12
3.4.1 Operation description .................................................................................................. 3-12
[Precautions for Hold function] ............................................................................................ 3-16