
TABLE OF CONTENTS
iv
EPSON
S1C33205 TECHNICAL MANUAL
Bus Clock............................................................................................................................................................B-II-4-18
Bus Speed Mode...............................................................................................................................B-II-4-19
Bus Clock Output...............................................................................................................................B-II-4-19
Bus Cycles in External System Interface................................................................................................B-II-4-20
SRAM Read Cycles ..........................................................................................................................B-II-4-20
Bus Timing ...........................................................................................................................................B-II-4-21
SRAM Write Cycles...........................................................................................................................B-II-4-22
Burst ROM Read Cycles.................................................................................................................B-II-4-24
DRAM Direct Interface ...................................................................................................................................B-II-4-25
Outline of DRAM Interface .............................................................................................................B-II-4-25
DRAM Setting Conditions ..............................................................................................................B-II-4-26
DRAM Read/Write Cycles ..............................................................................................................B-II-4-29
DRAM Refresh Cycles.....................................................................................................................B-II-4-32
Releasing External Bus.................................................................................................................................B-II-4-33
Power-down Control by External Device................................................................................................B-II-4-34
I/O Memory of BCU.........................................................................................................................................B-II-4-35
II-5 ITC (Interrupt Controller) ................................................................................. B-II-5-1
Outline of Interrupt Functions .........................................................................................................................B-II-5-1
Maskable Interrupts .............................................................................................................................B-II-5-1
Interrupt Factors and Intelligent DMA ...........................................................................................B-II-5-3
Nonmaskable Interrupt (NMI)...........................................................................................................B-II-5-3
Interrupt Processing by the CPU ....................................................................................................B-II-5-3
Clearing Standby Mode by Interrupts ...........................................................................................B-II-5-3
Trap Table .............................................................................................................................................................B-II-5-4
Control of Maskable Interrupts.......................................................................................................................B-II-5-5
Structure of the Interrupt Controller ...............................................................................................B-II-5-5
Processor Status Register (PSR)...................................................................................................B-II-5-5
Interrupt Factor Flag and Interrupt Enable Register................................................................B-II-5-6
Interrupt Priority Register and Interrupt Levels..........................................................................B-II-5-8
IDMA Invocation ..................................................................................................................................................B-II-5-9
HSDMA Invocation ..........................................................................................................................................B-II-5-11
I/O Memory of Interrupt Controller.............................................................................................................B-II-5-12
Programming Notes ........................................................................................................................................B-II-5-25
II-6 CLG (Clock Generator) .................................................................................... B-II-6-1
Configuration of Clock Generator .................................................................................................................B-II-6-1
I/O Pins of Clock Generator............................................................................................................................B-II-6-2
High-Speed (OSC3) Oscillation Circuit.......................................................................................................B-II-6-2
PLL .........................................................................................................................................................................B-II-6-3
Controlling Oscillation........................................................................................................................................B-II-6-3
Setting and Switching Over the CPU Operating Clock.........................................................................B-II-6-4
Power-Control Register Protection Flag.....................................................................................................B-II-6-5
Operation in Standby Mode............................................................................................................................B-II-6-5
I/O Memory of Clock Generator ....................................................................................................................B-II-6-6
Programming Notes ...........................................................................................................................................B-II-6-9
II-7 DBG (Debug Unit)............................................................................................ B-II-7-1
Debug Circuit........................................................................................................................................................B-II-7-1
I/O Pins of Debug Circuit..................................................................................................................................B-II-7-1