| RabbitCore RCM2200 User's Manual |
Appendix A. RabbitCore RCM2200 Specifications
Appendix A provides the specifications for the RCM2200, and describes the conformal coating.
A.1 Electrical and Mechanical Characteristics
Figure A-1 shows the mechanical dimensions for the RCM2200.
Table A-1 provides the pin 1 locations for the RCM2200 headers viewed from the top side (as in Figure A-1).
Table A-1. RCM2200 Header Pin 1 Locations RabbitCore RCM2200 user board interface RabbitCore RCM2200 user board interface Programming header (top side) LNK LED ACT LED It is recommended that you allow for an "exclusion zone" of 0.04" (1 mm) around the RCM2200 in all directions when the RCM2200 is incorporated into an assembly that includes other printed circuit boards. This "exclusion zone" that you keep free of other components and boards will allow for sufficient air flow, and will help to minimize any electrical or EMI interference between adjacent boards. An "exclusion zone" of 0.12" (3 mm) is recommended below the RCM2200 when the RCM2200 is plugged into another assembly using the shortest connectors for headers J4 and J5. Figure A-2 shows this "exclusion zone."
Table A-2 lists the electrical, mechanical, and environmental specifications for the RCM2200.
A.1.1 Headers
The RCM2200 uses headers at J4 and J5 for physical connection to other boards. J4 and J5 are 2 × 13 SMT headers with a 2 mm pin spacing. J1, the programming port, is a 2 × 5 header with a 2 mm pin spacing.
Figure A-3 shows the layout of another board for the RCM2200 to be plugged into. These values are relative to the header connectors.
A.1.2 Physical Mounting
A 9/32" (7 mm) standoff with a 4-40 screw is recommended to attach the RCM2200 to a user board at the hole position shown in Figure A-3. Either use plastic hardware, or use insulating washers to keep any metal hardware from shorting out signals on the RCM2200.
A.2 Bus Loading
You must pay careful attention to bus loading when designing an interface to the RCM2200. This section provides bus loading information for external devices.
Table A-3 lists the capacitance for the various RCM2200 I/O ports.
Table A-3. Capacitance of Rabbit 2000 I/O Ports Parallel Ports A to E Data Lines BD0-BD7 Address Lines BA0-BA12 Figure A-4 shows a typical timing diagram for the Rabbit 2000 microprocessor external memory read and write cycles.
Tadr is the time required for the address output to reach 0.8 V. This time depends on the bus loading. Tsetup is the data setup time relative to the clock. Tsetup is specified from 30%/70% of the VDD voltage level.
Table A-4 lists the parameters shown in these figures and provides minimum or measured values.
A.3 Rabbit 2000 DC Characteristics
Table A-5 outlines the DC characteristics for the Rabbit 2000 at 5.0 V over the recommended operating temperature range from Ta = -40°C to +85°C, VDD = 4.5 V to 5.5 V.
Table A-5. 5.0 Volt DC Characteristics Input Leakage High VIN = VDD, VDD = 5.5 V Input Leakage Low
(no pull-up)VIN = VSS, VDD = 5.5 V Output Leakage (no pull-up) VIN = VDD or VSS,
VDD = 5.5 VCMOS Input Low Voltage CMOS Input High Voltage CMOS Switching Threshold VDD = 5.0 V, 25°C CMOS Output Low Voltage IOL = See Table A-6 (sinking) VDD = 4.5 V CMOS Output High Voltage IOH = See Table A-6 (sourcing) VDD = 4.5 V A.4 I/O Buffer Sourcing and Sinking Limit
Unless otherwise specified, the Rabbit I/O buffers are capable of sourcing and sinking 8 mA of current per pin at full AC switching speed. Full AC switching assumes a 25.8 MHz CPU clock and capacitive loading on address and data lines of less than 100 pF per pin. Address pin A0 and data pin D0 are rated at 16 mA each. Pins A1-A12 and D1-D7 are each rated at 8 mA. The absolute maximum operating voltage on all I/O is VDD + 0.5 V or 5.5 V.
Table A-6 shows the AC and DC output drive limits of the parallel I/O buffers when the Rabbit 2000 is used in the RCM2200.
Table A-6. I/O Buffer Sourcing and Sinking Capability Output Port Name Full AC Switching SRC/SNK Maximum3 DC Output Drive SRC/SNK PA [7:0] 8/8 12/12 PB [7, 1, 0] 8/8 12/12 PC [6, 2, 0] 8/8 12/12 PD [5:4] 8/8 12/12 PD34 16/16 25/25 PE [7, 5, 4, 1, 0] 8/8 12/12
1 The maximum DC sourcing current for I/O buffers between VDD pins is 112 mA.
2 The maximum DC sinking current for I/O buffers between VSS pins is 150 mA.
3 The maximum DC output drive on I/O buffers must be adjusted to take into consideration the current demands made my AC switching outputs, capacitive loading on switching outputs, and switching voltage.
The current drawn by all switching and nonswitching I/O must not exceed the limits specified in the first two footnotes.
4 The combined sourcing from Port D [7:0] may need to be adjusted so as not to exceed the 112 mA sourcing limit requirement specified in the first footnote.
A.5 Conformal Coating
The areas around the 32 kHz real-time clock crystal oscillator has had the Dow Corning silicone-based 1-2620 conformal coating applied. The conformally coated area is shown in Figure A-5. The conformal coating protects these high-impedance circuits from the effects of moisture and contaminants over time.
Any components in the conformally coated area may be replaced using standard soldering procedures for surface-mounted components. A new conformal coating should then be applied to offer continuing protection against the effects of moisture and contaminants.
NOTE For more information on conformal coatings, refer to Technical Note 303, Conformal Coatings.
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