Open-Drain Outputs Used for Key Scan | Jameco Electronics 3000

4.2 Open-Drain Outputs Used for Key Scan

The Parallel Port D outputs can be individually programmed to be open drain. This is use- ful for scanning a switch matrix, as shown in Figure 4-2.A row is driven low, then the col- umns are scanned for a low input line, which indicates a key is closed. This is repeated for each row. The advantage of using open-drain outputs is that if two keys in the same col- umn are depressed, there will not be a fight between a driver driving the line high and another driver driving it low.

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o.d.
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o.d.

Figure 4-2. Using Open-Drain Outputs for Key Scan

User’s Manual

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Image 60

Jameco Electronics 3000, 2000 manual Open-Drain Outputs Used for Key Scan, Using Open-Drain Outputs for Key Scan

Contents

Page Rabbit 3000 Microprocessor Trademarks Rabbit Semiconductor Table of Contents Rabbit Internal I/O Registers Parallel Ports 129 Rabbit 3000 Clocks 209 Appendix B. Rabbit 3000 Revisions 273 Rabbit 3000 Microprocessor Introduction Features and Specifications Rabbit User’s Manual 1shows a block diagram of the Rabbit CPU Summary of Rabbit 3000 Advantages Feature Rabbit Differences Rabbit 3000 vs. Rabbit Serial ports with support for SDLC/HDLC IrDA Rabbit 3000 Design Features Rabbit 8-bit Processor vs. Other Processors Overview of On-Chip Peripherals and Features 1 5 V Tolerant InputsSerial Ports System Clock 4 32.768 kHz Oscillator Input Parallel I/O Cascaded Output Registers for Parallel Ports D and E Slave Port Rabbit Timers Auxiliary I/O Bus Input Capture Channels PWM Quadrature Encoder Inputs Pulse Width Modulation Outputs Separate Core and I/O Power Pins Design StandardsSpread Spectrum Clock Programming Port Standard Bios Dynamic C Support for the Rabbit Rabbit 3000 Microprocessor Details on Rabbit Microprocessor Features Processor Registers Rabbit 3000 Microprocessor Memory Mapping Addressing Memory Components Example of Memory Mapping Operation 4shows a memory interface unit Extended Code Space Separate I and D Space Extending Data Memory Use of XPC Segment Xpc window stack Using the Stack Segment for Data Storage Practical Memory Considerations Data RAM Root Code User’s Manual Instruction Set Outline Load Immediate Data to a Register Load or Store Data from or to a Constant Address Load or Store Data Using an Index Register Other 8-bit loads and stores are the following Register-to-Register Move Register Exchanges Push and Pop Instructions 7 16-bit Arithmetic and Logical Ops Bool SBC instruction can also be used to perform a sign extension Input/Output Instructions How to Do It in Assembly Language-Tips and Tricks Zero HL in 4 ClocksExchanges Not Directly Implemented Manipulation of Boolean Variables Comparisons of Integers HLB Atomic Moves from Memory to I/O Space Interrupt Structure Interrupt Priority Effect of Processor Priorities on Interrupts Processor Priority Effect on Interrupts Multiple External Interrupting Devices Privileged Instructions, Critical Sections and Semaphores Semaphores Using Bit B,HL Critical Sections Computed Long Calls and Jumps Rabbit Capabilities Precisely Timed Output Pulses Pulse Width Modulation to Reduce Relay Power Using Open-Drain Outputs for Key Scan Open-Drain Outputs Used for Key Scan Cold Boot Slave Port Slave Rabbit As a Protocol Uart PIN Assignments and Functions Lqfp Package Pinout Mechanical Dimensions and Land Pattern Same pin dimensions apply along the x axis and the y axis PC Board Land Pattern for Rabbit 3000 128-pin Lqfp C D E F G H J K L M Ball Grid Array Package Ball and Land Size Dimensions Design Considerations All dimensions in mmKey Feature Recommendation Nominal Ball Tolerance Ball Pitch Nominal Land BGA Package Outline Rabbit Pin Descriptions Rabbit Pin DescriptionsPin Pin Group Pin Name Direction Function Numbers Lqfp Tfbga Vddcore Bus Timing Bus Timing Read and Write Description of Pins with Alternate Functions Pins With Alternate Functions PF7 PWM3 AQD2A Parallel Port x Alternate Functions Parallel Port x Alternate Functions Control Bits DC Characteristics 3 Volt DC CharacteristicsSymbol Parameter Maximum Rating Symbol Parameter Test Conditions Min Typ Max Units I/O Buffer Sourcing and Sinking Limit Rabbit 3000 Microprocessor Rabbit Internal I/O Registers Rabbit 3000 Peripherals and Interrupt Service Vectors On-Chip Peripheral ISR Starting Address Default Values for all the Peripheral Control Registers Register Name Mnemonic Address ResetRabbit Internal I/O Registers Grev PEB7R PWM0R Tbcsr Sdar Global ROM Configuration Register Global RAM Configuration RegisterMiscellaneous Functions Processor Identification Rabbit Oscillators and Clocks Global CPU RegisterGlobal Revision Register Gcpu Rabbit Global Control/Status Register Clock Select Field of GcsrGlobal Control/Status Register Gcsr Recommended Delays Set In Gcdr for Clock Doubler Clock DoublerGlobal Clock Double Register Gcdr Effect of Clock Doubler User’s Manual Clock Spectrum Spreader Reduction in Peak Spectral Strength from Spectrum Spreader Chip Select Options for Low Power Global Power Save Control Register Address = 0x0D Short Chip Select Memory Read Output Pins CLK, STATUS, /WDTOUT, /BUFEN Global Output Control Register Gocr = 0x0E Time/Date Clock Real-Time Clock 10. Real-Time Clock RTCxR Data Registers 11. Real-Time Clock Control Register Rtccr adr = Watchdog Timer 12. Watchdog Timer Control Register Wdtcr adr = 13. Watchdog Timer Test Register Wdttr adr = System Reset 14. Rabbit 3000 Reset Sequence and State of I/O Pins Pin Name Direction Reset Low Post-Reset† Recognized by CPU Rabbit Interrupt Structure 15. Interrupts-Priority and Action to Clear Requests External Interrupts External Interrupt Line Logic Interrupt Vectors INT0 EIR,0x00/INT1 EIR,0x08 16. Control Registers for External InterruptsReg Name Reg Address Bits 7,6 Bits 5,4 Bits 3,2 Bits 1,0 Bootstrap Operation 102 Rabbit 3000 Microprocessor Pulse Width Modulator Pulse Width LSBs 1st 2nd 3rd 4th 17. PWM LSB x Register 18. PWM MSB x Register Input Capture 106 Rabbit 3000 Microprocessor 19. Input Capture Control/Status Register Input Capture Control/Status RegisterIccsr 20. Input Capture Control Register 21. Input Capture Trigger x RegisterIccr ICT1R 22. Input Capture Source x Register 23. Input Capture LSB x Register24. Input Capture MSB x Register Quadrature Decoder Rejected 25. Quadrature Decoder Control/Status Register Quad Decode Control/Status RegisterQdcsr 26. Quadrature Decoder Control Register 27. Quadrature Decoder Count RegisterQdcr QDC1R 114 Rabbit 3000 Microprocessor Memory Interface and Mapping Interface for Static Memory Chips Rabbit Data Lines Static Address Lines Memory FlashRAM Memory Mapping Overview Memory-Mapping UnitProcessor Memory Mapping Unit Interface Memory Chips 64K Segment RegistersSegment Size Register Segment Register Function Memory Interface Unit Memory Bank Control Registers Memory Bank Control Register x MBxCR = 0x014 + Optional A16, A19 Inversions by Segment /CS1 Enable MMU Instruction/Data Register Mmidr =MMU Instruction/Data Register Mmidr Memory Timing Control Register MTCR, adr = MMU Expanded Code RegisterMecr Memory Timing Control Register Allocation of Extended Code and Data Breakpoint/Debug Control Register BDCR, adr = 0x01CBreakpoint/Debug Control Register Bdcr Instruction and Data Space Support RAM Use of Physical Memory Separate I & D Space Model How the Compiler Compiles to Memory 128 Rabbit 3000 Microprocessor Parallel Ports Parallel Port a Parallel Port a RegistersParallel Port a Data Register Bit Functions Parallel Port B Parallel Port B RegistersParallel Port B Register Bit Functions Parallel Port C Parallel Port C RegistersParallel Port C Register Bit Functions Parallel Port D Parallel Port D Registers PD7 Parallel Port D Register functions Parallel Port D Control Register adr =Bits 7 Bits 5 Bits 3 Bits 1 136 Rabbit 3000 Microprocessor Parallel Port E PE0 10. Parallel Port E Registers 11. Parallel Port E Register functions 12. Parallel Port E Control Register adr = Parallel Port F 13. Parallel Port F Registers14. Parallel Port F Register Functions Using Parallel Port a and Parallel Port F 15. Parallel Port F Control Register adr = 0x03C Summary Parallel Port a Parallel Port F Parallel Port G 16. Parallel Port G Registers17. Parallel Port G Data Register Functions Parallel Port G Control Register adr= 0x04C 10. I/O Bank Control Registers Write data Write strobe T1 Tw T2Read data Read strobe Chip select strobe External I/O Timing with 1 wait state I/O Bank x Control Register External I/O Register Address Range and Pin Mapping Control Register Port E Address Pin A1513 Range 148 Rabbit 3000 Microprocessor Timers Timer a Reload Register Operation Timer a I/O Registers Timer a I/O Registers Timer a Capabilities Timer a Control and Status RegisterTacsr User’s Manual 153 Timer a Control Register Timer a Prescale RegisterTacr Tapr Practical Use of Timer a Timer B Timer B RegistersRegister Name Mnemonic Reset Address Timer B Control and Status Register Timer B Control RegisterTbcsr Tbcr Timer B Count MSB x Registers 10. Timer B Count LSB x Registers11. Timer B Count MSB Register 12. Timer B Count LSB Register Using Timer B 160 Rabbit 3000 Microprocessor Serial Port Signals Serial Port Signal Name FunctionRabbit Serial Ports Clka User’s Manual 163 Signals Shown at Microprocessor Tx Pin Serial Port Register Layout User’s Manual 165 Serial Port Registers Serial Port a RegistersSerial Port B Registers Serial Port C Registers Serial Port D Registers Serial Port E RegistersSerial Port F Registers Data Register All Ports Address Register All Ports 10. Long Stop Register All Ports 11. Status Register Asynchronous Mode Only All Ports Bits Value Description Clocked serial mode only 12. Status Register Clocked Serial Ports A-D only 13. Status Register Hdlc Mode Ports E and F only Bits Value Description Hdlc mode only 14. Serial Port Control Register Ports a and B SacrSbcr 15. Serial Port Control Register Ports C and D SccrAddress = 0xE4 Sdcr 16. Serial Port Control Register Ports E and F SecrAddress = 0xCC Sfcr 17. Extended Register Asynchronous Mode All Ports 18. Extended Register Clocked Serial Mode Ports A-D only 19. Extended Register Hdlc Mode Ports E and F only Serial Port Interrupt Transmitter IRQ Transmit Serial Data Timing Receive Serial Data Timing Serial Port Synchronization Clock Polarities Supported in Clocked Serial Mode Clocked Serial Ports User’s Manual 183 184 Rabbit 3000 Microprocessor Clocked Serial Timing Clocked Serial Timing With Internal ClockClocked Serial Timing with External Clock Valid Synchronous Communications on Ports E and F Last Byte Bit Pattern Valid Data Hits User’s Manual 189 190 Rabbit 3000 Microprocessor User’s Manual 191 Serial Port Software Suggestions Push AF IOI LD A,SCSR Controlling an RS-485 Driver and Receiver Transmitting Dummy Characters Using a Serial Port to Generate a Periodic Interrupt Transmitting and Detecting a Break Parity, Extra Stop Bits with 7-Data-Bit Characters Parity, Extra Stop Bits with 8-Data-Bit CharactersStop bit Start bit Data bits 9th bit low Stop bit Supporting 9th Bit Communication Protocols Rabbit-Only Master/Slave ProtocolData Framing/Modbus User’s Manual 197 198 Rabbit 3000 Microprocessor Rabbit Slave Port SRD SCS Slave Port Read Cycle Symbol Parameter Minimum Maximum Following table explains the parameters used in Figure Slaveattn PB7 Typical Connection Slave Rabbit to Master Rabbit Hardware Design of Slave Port Interconnection Slave Port RegistersSlave Port Registers Register Mnemonic Internal Address External Address Slave Port Control Register Spcr adr = Bit Bits 6,5 Bit 3,2 Bits 1,0 Write Only Read Only Applications and Communications Protocols for Slaves Slave ApplicationsSlave Port Status Register Spsr adr = Master-Slave Messaging Protocol 208 Rabbit 3000 Microprocessor Rabbit 3000 Clocks Rabbit 3000 Main Oscillator Circuit Low-Power Design EMI Control Power Supply Connections and Board Layout Using the Clock Spectrum Spreader Spread Spectrum Enable/Disable Register Spread Spectrum Mode SelectGCM0R GCM1R 214 Rabbit 3000 Microprocessor AC Timing Specifications Memory Access TimeAccess Enable Access MHz Memory Requirements at 3.3 V, -40C to +85C, Adr Bus 60 pF Data and Clock Delays VDD ±10%, Temp, -40C-+85C maximum VDDNormal Strong 30 pF 60 pF 90 pF No dbl/dbl CSx Memory Read Time Delays Memory Write Time DelaysTime Delay Output Capacitance 30 pF 60 pF 90 pF CLK A190 CSx WEx D70 Example Clock Doubler Max-Min Clock Low Times 222 Rabbit 3000 Microprocessor 16.2 I/O Access Time Bufen I/O Read Time Delays I/O Write Time Delays Further Discussion of Bus and Clock Timing Clock Doubler and Memory Timing Maximum Clock Speeds Maximum Clock Speeds at 3.3 V PreliminaryConditions Commercial Ratings Industrial Ratings Period Frequency External Oscillator Buffer Power and Current Consumption User’s Manual 229 Rabbit 3000 System Current vs. Frequency at 3.3 11. Sleepy Mode Current Consumption Current Consumption Mechanisms Sleepy Mode Current Consumption Memory Current Consumption Battery-Backed Clock Current Consumption Current is negligible for V 1.14 Reduced-Power External Main Oscillator Voltage Current incl built-in buffer Rabbit Bios and Virtual Driver BiosBios Services Bios Assumptions Watchdog Timer SupportVirtual Driver Periodic Interrupt User’s Manual 239 240 Rabbit 3000 Microprocessor Power Management Support Other Rabbit Software Using Assembly Language Using Library FunctionsReading and Writing I/O Registers Shadow Registers Updating Shadow RegistersInterrupt While Updating Registers Atomic Instruction Timer and Clock Usage Write-only Registers Without Shadow RegistersNon-atomic Instructions Format of the structure used is the following 246 Rabbit 3000 Microprocessor Rabbit Instructions Summary Spreadsheet Conventions Flag Description Symbols Rabbit Z180 Meaning Load Immediate Data Load & Store to Immediate Address19.3 8-bit Indexed Load and Store 19.4 16-bit Indexed Loads and Stores 19.5 16-bit Load and Store 20-bit Address Register to Register Moves Exchange Instructions Stack Manipulation Instructions19.9 16-bit Arithmetic and Logical Ops 19.10 8-bit Arithmetic and Logical Ops ADD A,HL 19.11 8-bit Bit Set, Reset and Test 19.12 8-bit Increment and Decrement 19.13 8-bit Fast a Register Operations 19.14 8-bit Shifts and Rotates Instruction Prefixes Block Move Instructions Control Instructions Jumps and Calls Miscellaneous Instructions Privileged Instructions Following instructions are privileged Differences Rabbit VS. Z80/Z180 Instructions Z80/Z180 Instructions Dropped Rabbit Instructions to Use IOI and IOE I Column Symbol Key Flag Register Key Rabbit Z180 Meaning Z V C EX AF,AF LD A,BC LDP HL,IX RRA 268 Rabbit 3000 Microprocessor Appendix A. the Rabbit Programming Port Programming Port PIN Assignments Use of the Programming Port as a Diagnostic/Setup Port Alternate Programming Port Suggested Rabbit Crystal Frequencies Non-Stock Crystals Appendix B. Rabbit 3000 Revisions 274 Rabbit 3000 Microprocessor User’s Manual 275 Discussion of Fixes and Improvements Table B-1. Summary of Rabbit 3000 Improvements and FixesRabbit Description 3000 3000A IL1T/IZ1T IL2T/IZ2T Table B-2. Reset State of New Rabbit 3000A I/O Registers Rabbit Internal I/O Registers Iuer Rabbit Register Name Mnemonic 3000 3000A Address Reset Peripheral and ISR Address On-Chip Peripheral Address Range ISR Starting Address User’s Manual 281 Revision-Level ID Register Table B-5. Rabbit 3000 Revision Identification InformationProcessor Revision Package Gcpu Grev System/User Mode Memory Protection Table B-6. Write Protect Control RegisterWrite Protect Control Register Wpcr Table B-7. Write Protect Low Register Write Protect Low RegisterWplr Table B-8. Write Protect High Register Table B-9. Write Protect Segment x RegisterWphr Wpsar Table B-10. Write Protect Segment x Low Register Write Protect Segment x Low RegisterWpsalr Wpsblr Table B-11. Write Protect Segment x High Register Write Protect Segment x High RegisterWpsahr Wpsbhr Stack Protection Figure B-2. Simple Stack Protection Layout Table B-12. Stack Limit Control Register Table B-13. Stack Low Limit RegisterTable B-14. Stack High Limit Register RAM Segment Relocation Table B-15. RAM Segment RegisterRAM Segment Register Ramsr Secondary Watchdog Timer Table B-16. Watchdog Timer Control Register-UpdatedTable B-17. Secondary Watchdog Timer Register Wdtcr New Opcodes Table B-18. New Rabbit 3000 OpcodesInstruction Bytes Clks Operation New UMA/UMS Opcodes Table B-19. Rabbit 3000 Revision Block Copy Opcode Effects New Block Copy OpcodesSource Destination IOI/IOE Expanded I/O Memory Addressing Table B-20. MMU Instruction/Data Register External I/O Improvements Table B-21 Bank x Control Register Table B-22. Global Power Save Control Register Short Chip Select Timing for WritesAddress = 0x000D Clock Select and Power Save Modes Table B-23. Global Control/Status RegisterTable B-24. Clock Select Field of Gcsr Short Chip Select Timing Figure B-3. Short Chip Select Timing CLK/8, Read Operation Figure B-4. Short Chip Select Timing CLK/6, Read Operation Figure B-6. Short Chip Select Timing CLK/2, Read Operation Figure B-7. Short Chip Select Timing 2 kHz, Read Operation Figure B-9. Short Chip Select Timing 8 kHz, Read Operation Figure B-11. Short Chip Select Timing 32 kHz, Read Operation Figure B-12. Short Chip Select Timing CLK/8, Write Operation Figure B-13. Short Chip Select Timing CLK/6, Write Operation Figure B-15. Short Chip Select Timing CLK/2, Write Operation Figure B-16. Short Chip Select Timing 2 kHz, Write Operation Figure B-18. Short Chip Select Timing 8 kHz, Write Operation 310 Rabbit 3000 Microprocessor Pulse Width Modulator Improvements Figure B-21. PWM Interrupt and Output Timing Table B-25. PWM LSB 0 Register Table B-26. PWM LSB 1 RegisterPWM LSB 0 Register PWM LSB 1 Register Table B-27. PWM LSB 2 and 3 Registers Address = 0x008CAddress = 0x008E Quadrature Decoder Improvements Table B-28. Quadrature Decoder Control RegisterTable B-29. Quadrature Decoder Count High Register QDC1HR User’s Manual 315 Pins with Alternate Functions Serial Ports E/F Appendix C. SYSTEM/USER Mode System Mode User ModeTable C-1. Differences Between System and User Modes System/User Mode Opcodes Table C-2. New System/User Mode OpcodesInstruction Bytes Clk Operation Priv System/User Mode Registers Table C-3. System/User Mode I/O Registers Table C-4. I/O Addresses Inaccessible in User Mode Register Name Mnemonic Address Figure C-1. Interrupt Handing in System/User Mode Interrupts Peripheral Interrupt Prioritization Table C-5. Interrupts-Priority and Action to Clear Requests Using the System/User Mode Memory Protection Only Mixed System/User Mode Operation Figure C-3. System/User Mode Setup for Mixed Operation Figure C-4. System/User Mode Setup for Operating System Complete Operating System Appendix D. Rabbit 3000A Internal I/O Registers Table D-1 Rabbit 3000A Internal I/O Registers Table D-1. Rabbit 3000A Internal I/O Registers 0x03C0 00000000 Serial Port E User Enable Register 0x006A Xxxxxxxx Port D Bit 3 Register 0x0082 00000000 Bank 3 Control Register 0x0098 Xx000000 Interrupt 1 Control Register 0x00D1 Xxxxxxxx Serial Port B Long Stop Register 334 Rabbit 3000 Microprocessor User’s Manual 335 Page Index Numerics Memory A16, A19 inversions /CS1 PWL2R, PWL3R 200