RCA CDP18S711 manual Operating System Register Table, Operating System Summary

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34	RCA COSMAC VIP Instruction Manual

Operating System Register Table

Memory	Register	Memory	Register
Address	Byte	Address	Byte,
0XB0		0XC0
0XB1		0XC1
0XB2		0XC2
0XB3	R3.0	0XC3	R3.1
0XB4	R4.0	0XC4	R4.1
0XB5	R5.0	0XC5	R5.1
0XB6	R6.0	0XC6	R6.1
0XB7	R7.0	0XC7	R7.1
0XB8	R&0	0XC8	R8.1
0XB9	R9.0	0XC9	R9.1
0XBA	RA.0	0XCA	RA.1
0XBB	RB.0	0XCB	RB.1
0XBC	RC.0	0XCC	RC.1
0XBD	RD.0	0XCD	RD.1
0XBE	RE.0	0XCE	RE.1
0XBF	RF.0	0XCF	RF.1

0X = 07 for 2048-byte RAM

0X = 0B for 3072-byte RAM

0X = 0F for 4096-byte RAM

R5 = CHIP-8 language program counter RA = CHIP-8 language I pointer

R3 = Machine Language Subroutine Program Counter

Operating System Summary

1.RUN up with key C pressed selects operating system at 8000.

2.Enter four-digit address followed by mode digit:

AMR (Memory Read)

0 MW (Memory Write)

BTR (Tape Read)

FTW (Tape Write)

3.CDP1802 microprocessor registers are stored as shown in table above. They may be examined after a program is run by using operating system mode A.

4.Mode 0 can be used to insert temporary stops in a program for debugging purposes. Insert a "branch-to-itself" instruction at the desired stopping point.

5.The operating system uses the top 84 bytes of RAM (0XAC-0XFF). Avoid using these byte locations in your programs.

6.The operating system searches for and uses the top (highest) 256-byte page of on-card RAM. When RUN is flipped up to execute a program, beginning at 0000, the following initial conditions exist:

P=0, Q=0, R0=0000, and R1 =0XFF where 0X highest page of on-card RAM.

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Contents Page VIP-311 RCA COSMAC VIP CDP18S711 Instruction ManualACKNOWLEDGMENT Contents Contents Continued What This Manual Covers 1. Getting StartedThe Power Supply What You See Turning It On1. Getting Started Using the Operating System 11.COSMAC VIP OperationMemory Write Memory Read Tape WriteTape Read 11.COSMAC VIP Operation Testing Your Cassette SystemHow to Change and Use the Variables III.CHIP-8Language ProgrammingBranch Instructions Using the Display Instructions 0200 A20A I=020A 0202 6100 V1=00 0204 6200 V2=00 III. CHIP-8 Language Programming0206 D125 SHOW 5MI@VlV2 0208 1208 GO 020A F090 020C F090 020E F000Applying CHIP-8 111. CHIP-8Language Programming Some Program Ideas25.PROGRAMMED SPOT - Introduce children to programming concepts by letting them preprogram the movements of a spot or object on the screen VIP Machine Coding IV. Machine Language ProgrammingMachine Language Programming Summed Up V. Logic Description How Memory Is AddressedHow the Input/Output Works pressed. A 62 machine instruction causes the least significant 4 bits of memory byte to be latched into U13. These 4 bits are decoded to bring one of the 16 U13 output lines low. If the key that corresponds to this output line is pressed, the CDPI802 EF3 input will go low. The 4-bitcodes latched into U13 correspond to the equivalent key positions. After the program send8 a 4-bitcode to U13, it subsequently examines the EF3 line to see if the key corresponding to this code is pressed or not. In this manner, a program can determine when any specific key is pressed or can sequentially scan all keys while waiting for any one to be pressed. Key debounce delays must be provided in the program when required. A program can also cause a speaker tone to occur when a key is pressed. Only one key at a time should be pressed with this method of interfacing the keyboard V1. Expansion Considerations and Connections Using the Byte Input/OutputUsing the Expansion Interface Some Expansion IdeasI RCA COSMAC VIP Instruction Manual Pin Signal V1. Expansion Considerations and ConnectionsTable III - External Option Terminal Connections 2.Composing poetry or pictures with printer output Other Problems VIL Troubleshooting HintsSignal Tracing No SoundLast Resorts Appendix A - Test and Operating Data Byte Pattern for Displaying COSMACBeeper Program Cassette Attachment Diagram Cassette Phase Test SignalsTest Program Cassette Data Test Memory Test Program Cassette Recording GuidelinesOperating System Listing Appendix B - Operating SystemOperating System Register Table Operating System SummaryR3 = Machine Language Subroutine Program Counter CHIP-8Interpreter Listing Appendix C - CHIP-8InterpreterCHIP-8Memory Map CDP1802 Register Use for CHIP-8Interpreter Appendix C - CHIP-8Interpreter RCA COSMAC VIP Instruction Manual CHIP-8User NotesPage 1. VIP Kaleidoscope 2. VIP Video Display Drawing Game Fig. E-5Power Supply Circuit and Byte Appendix E - Logic DiagramsFig. E-1Microprocessor and Display Interface CircuitsPage Appendix E - Logic Diagrams Fig. E-2- ROM Circuits and Expansion InterfacePage Appendix E - Logic Diagrams Fig. E-4- RAM CircuitsRCA COSMAC VIP Instruction Manuel RCA COSMAC VIP Instruction Manual Appendix F Board Layout, Parts List, and Expansion Notes2.Parts List for RCA COSMAC VIP CDP18S711 1.Printed Circuit Board LayoutRCA COSMAC VIP Instruction Manual Page 2. Parts List for RCA COSMAC VIP CDP18S711 Page Resistors - Supplied 1 /4 W except as noted RCA COSMAC VIP Instruction ManualPage 3. COSMAC VIP Expansion Notes