Rabbit 2000™ Microprocessor - UTN

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user can reduce this buffer size to the maximum of the master and target’s sector sizes if root dataspace is a problem, or increase it to 4096 if needed.Starting with Dynamic C version 7.02, the cloning implementation uses xmem for the buffer, soroot data space will not be a problem; and no changes should be made to FLASHWR.LIB.8.3.3 Design RestrictionsDigital I/O line PB1 should not be used in the design if cloning is to be be used.46 Rabbit 2000 Microprocessor
9. Low-Power Design and SupportTo get the most computation for a given power level, the operating voltage should be approximately3.3 V. At a given operating voltage, the clock speed should be reduced as much as possibleto obtain the minimum power consumption that is acceptable.Some applications, such as a control loop, may require a continuous amount of computationalpower. Other applications, such as slow data logging or a portable test instrument, may spendlong periods with low computational requirements interspersed with short periods of high computationalload.The current (and thus power) consumption of a microprocessor-based system generally consists ofa part that is independent of frequency and a part that depends on frequency. The part that is independentof frequency consists of leakage or current or current drawn by special circuits such aspullup resistors or circuits that continuously draw power. Ordinary CMOS logic uses power whenit is switching from one state to another, and this is the power that is dependent on frequency. Thepower drawn while switching is used to charge capacitance or is used when both N and P FETs aresimultaneously on for a brief period during a transition.Floating inputs or inputs that are not solidly either high or low can also draw current because bothN and P FETs are turned on at the same time. To avoid excessive power consumption, floatinginputs should not be included in a design (except that some inputs may float briefly during poweronsequencing). Most unused inputs on the Rabbit can be made into outputs by proper softwareinitialization to remove the floating property. Pullup resistors will be needed on a few inputs thatcannot be programmed as outputs. An alternative to a pullup resistor is to tie an unused output tothe unused inputs. If pullup (or pulldown) resistors are required, they should be made as large aspossible if the circuit in question has a substantial part of its duty cycle with current flowingthrough the resistor.Rabbit 2000forf/2disable f/2ext pinCLKMainOscillatorClockDoublerf/8CPU32 kHzOscillatorTo watchdog timer andtime/date clockPeripheralDevicesNote: Peripherals cannot be clocked slower than the CPU.Figure 13. Rabbit Clock DistributionDesigner’s Handbook 47
Page 1 and 2: Rabbit 2000 MicroprocessorDesigner
Page 3 and 4: Table of Contents1 Introduction ...
Page 5 and 6: Instructions Affected by the Wait S
Page 7 and 8: 1. IntroductionThis manual is inten
Page 9 and 10: 2. Rabbit Hardware DesignOverviewBe
Page 11 and 12: 2.3 Power ConsumptionWhen minimum p
Page 13 and 14: 3. Core Design and ComponentsCore d
Page 15 and 16: 3.2 Basic Memory DesignNormally /CS
Page 17 and 18: 3.3 PC Board Layout and Memory Line
Page 19 and 20: With a Rabbit-based system it is ea
Page 21 and 22: 3.4.2.3 High Frequency Oscillator C
Page 23 and 24: 3.4.2.4 Processor DecouplingThe int
Page 25 and 26: 4. How Dynamic C Cold Boots theTarg
Page 27 and 28: 4.2 Program Loading Process Overvie
Page 29 and 30: 5. Rabbit Memory OrganizationThe Ra
Page 31 and 32: 5.2.1 DefinitionsExtended Code: Ins
Page 33 and 34: 5.3.2 Paged Access in Extended Memo
Page 35 and 36: 6. The Rabbit BIOSWhen Dynamic C co
Page 37 and 38: 6.2 BIOS FlowchartThe following flo
Page 39 and 40: DATAORGBeginning logical address fo
Page 41 and 42: All origin statements must have a u
Page 43 and 44: 7. The System ID BlockThe BIOS supp
Page 45 and 46: 7.2 AccessThe BIOS will read the sy
Page 47 and 48: Table 4. The System ID Block (Conti
Page 49 and 50: 8. BIOS Support for ProgramCloningT
Page 51: 8.2.3 LED PatternsThe following tab
Page 55 and 56: 9.1 Software Support for Low-Power
Page 57 and 58: 10. Memory PlanningThe following re
Page 59 and 60: 11. Flash MemoriesThe flash memorie
Page 61 and 62: Table 7. 32-Pin Flash Memories Supp
Page 63 and 64: The field flashXPC contains the XPC
Page 65 and 66: 12. Troubleshooting Tips for NewRab
Page 67 and 68: 80 24 80 //terminate bootstrap, sta
Page 69 and 70: Appendix A. Supported Rabbit 2000Ba
Page 71 and 72: Appendix B.Wait State BugB.1 Overvi
Page 73 and 74: If the atomic nature of the operati
Page 75 and 76: B.4 Enabling Wait StatesMemory wait
Page 77: Legal NoticeRabbit Semiconductor pr

Rabbit 2000™ Microprocessor - UTN

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