Appendix A. RabbitCore RCM3000 Specifications

Appendix A provides the specifications for the RCM3000, and describes the conformal coating.

A.1 Electrical and Mechanical Characteristics

Figure A-1 shows the mechanical dimensions for the RCM3000.

Figure A-1. RCM3000 Dimensions

Table A-1 provides the pin 1 locations for the RCM3000 headers viewed from the top side (as in Figure A-1).

Table A-1. RCM3000 Header Pin 1 Locations

Header	Description	Pin 1 (x,y) Coordinates (Inches)
J1	RabbitCore RCM3000 user board interface	(1.689, 1.661)
J2	RabbitCore RCM3000 user board interface	(0.239, 1.661)
J3	Programming header (top side)	(0.254, 2.293)

It is recommended that you allow for an "exclusion zone" of 0.04" (1 mm) around the RCM3000 in all directions when the RCM3000 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 electromagnetic interference between adjacent boards. An "exclusion zone" of 0.08" (2 mm) is recommended below the RCM3000 when the RCM3000 is plugged into another assembly using the shortest connectors for headers J1 and J2. Figure A-2 shows this "exclusion zone."

Figure A-2. RCM3000 "Exclusion Zone"

Table A-2 lists the electrical, mechanical, and environmental specifications for the RCM3000.

Table A-2. RabbitCore RCM3000 Specifications 

Parameter	Specification
Board Size	1.850" × 2.725" × 0.86" (47 mm × 69 mm × 22 mm)
Operating Temperature	-40°C to +70°C
Humidity	5% to 95%, noncondensing
Input Voltage	3.15 V to 3.45 V DC
Current	145 mA at 29.4 MHz, 3.3 V DC; 10 mA additional with programming cable attached
General-Purpose I/O	52 parallel I/0 lines: 44 configurable for I/O, 4 fixed inputs, 4 fixed outputs
External Memory, I/O Interface	Alternate I/O bus can be configured for 8 data lines and 6 address lines (shared with parallel I/O lines), I/O read/write
Additional Digital Inputs	Startup mode (2), reset in
Additional Digital Outputs	Status, reset out
Ethernet Interface	10base-T
Microprocessor	Rabbit 3000TM
Clock	29.4 MHz
SRAM	128K × 8 or 512K × 8, surface mount
Flash Memory	One or two 256K × 8, surface mount
Timers	Ten 8-bit timers (6 cascadable), one 10-bit timer with 2 match registers
Pulse-Width Modulators	10-bit free-running counter and four pulse-width registers
Input Capture	2- channel input capture can be used to time input signals from various port pins
Quadrature Decoder	2-channel quadrature decoder accepts inputs from external incremental encoder modules
Infrared	Support for IRDA transceiver, 1.15Mbps
Serial Ports	6 CMOS-compatible ports, one of which is used as a programming port
Serial Rate	Maximum asynchronous1.84 Mbps Maximum synchronous 7.35 Mbps
Slave Interface	A slave port allows the RCM3000 to be used as an intelligent peripheral device slaved to a master processor, which may either be another Rabbit 3000 or any other type of processor
EMI Reduction	Spectrum spreader reduces radiated emissions
Watchdog/Supervisor	Yes
Time/Date Clock	Yes
Socket Strip (for connection to headers J4 and J5)	2x17, 2 mm pitch
Backup Battery	Provision for user-supplied backup battery (2.85 V to 3.15 V) via connections on header J2

A.1.1 Headers

The RCM3000 uses headers at J1 and J2 for physical connection to other boards. J1 and J2 are 2 ×  17 SMT headers with a 2 mm pin spacing. J3, 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 RCM3000 to be plugged into. These values are relative to the mounting hole.

A.1.2 Physical Mounting

A 9/32" (7 mm) standoff with a 2-56 screw is recommended to attach the RCM3000 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 RCM3000.

Figure A-3. User Board Footprint for RCM3000

A.2 Bus Loading

You must pay careful attention to bus loading when designing an interface to the RCM3000. This section provides bus loading information for external devices.

Table A-3 lists the capacitance for the various RCM3000 I/O ports.

Table A-3. Capacitance of Rabbit 3000 I/O Ports

I/O Ports	Input Capacitance (pF)	Output Capacitance (pF)
Parallel Ports A to G	12	14

Table A-4 lists the external capacitive bus loading for the various RCM3000 output ports. Be sure to add the loads for the devices you are using in your custom system and verify that they do not exceed the values in Table A-4.

Table A-4. External Capacitive Bus Loading -40°C to +70°C

Output Port	Clock Speed (MHz)	Maximum External Capacitive Loading (pF)
All I/O lines with clock doubler enabled	29.4	30-70
All I/O lines with clock doubler disabled	14.7456	100

Figure A-4 shows a typical timing diagram for the Rabbit 3000 microprocessor external memory read and write cycles.

Figure A-4. Memory Read and Write Cycles

Table A-5 lists the delays in gross memory access time for several values of V_DD.

Table A-5. Data and Clock Delays VDD ±10%, Temp, -40°C-+85°C (maximum)

VDD	Clock to Address Output Delay (ns)			Data Setup Time Delay (ns)	Spectrum Spreader Delay (ns)
	30 pF	60 pF	90 pF		Normal dbl/no dbl	Strong dbl/no dbl
3.3	6	8	11	1	3/4.5	4.5/9
2.7	7	10	13	1.5	3.5/5.5	5.5/11
2.5	8	11	15	1.5	4/6	6/12
1.8	18	24	33	3	8/12	11/22

The measurements are taken at the 50% points under the following conditions.

• T = -40°C to 85°C, V = V_DD ±10%

• Internal clock to nonloaded CLK pin delay # 1 ns @ 85°V/4.5 V

The clock to address output delays are similar, and apply to the following delays.

• T_adr, the clock to address delay

• T_CSx, the clock to memory chip select delay

• T_WEx, the clock to memory write strobe delay

• T_IOCSx, the clock to I/O chip select delay

• T_IORD, the clock to I/O read strobe delay

• T_IOWR, the clock to I/O write strobe delay

• T_BUFEN, the clock to I/O buffer enable delay

The data setup time delays are similar for both T_setup and T_hold.

When the spectrum spreader is enabled with the clock doubler, every other clock cycle is shortened (sometimes lengthened) by a maximum amount given in the table above. The shortening takes place by shortening the high part of the clock. If the doubler is not enabled, then every clock is shortened during the low part of the clock period. The maximum shortening for a pair of clocks combined is shown in the table.

A.3 Rabbit 3000 DC Characteristics

Table A-6 outlines the DC characteristics for the Rabbit at 3.3 V over the recommended operating temperature range from T_a = -55°C to +125°C, V_DD = 3.0 V to 3.6 V.

Table A-6. 3.3 Volt DC Characteristics

Symbol	Parameter	Test Conditions	Min	Typ	Max	Units
IIH	Input Leakage High	VIN = VDD, VDD = 3.3 V			1	µA
IIL	Input Leakage Low (no pull-up)	VIN = VSS, VDD = 3.3 V	-1			µA
IOZ	Output Leakage (no pull-up)	VIN = VDD or VSS, VDD = 3.3 V	-1		1	µA
VIL	CMOS Input Low Voltage				0.3 x VDD	V
VIH	CMOS Input High Voltage		0.7 x VDD			V
VT	CMOS Switching Threshold	VDD = 3.3 V, 25°C		1.65		V
VOL	Low-Level Output Voltage	IOL = See (sinking) VDD = 3.0 V			0.4	V
VOH	High-Level Output Voltage	IOH = See (sourcing) VDD = 3.0 V	0.7 x VDD			V

A.4 I/O Buffer Sourcing and Sinking Limit

Unless otherwise specified, the Rabbit I/O buffers are capable of sourcing and sinking 6.8 mA of current per pin at full AC switching speed. Full AC switching assumes a 29.4 MHz CPU clock and capacitive loading on address and data lines of less than 70 pF per pin. The absolute maximum operating voltage on all I/O is 5.5 V.

Table A-7 shows the AC and DC output drive limits of the parallel I/O buffers when the Rabbit 3000 is used in the RCM3000.

Table A-7. I/O Buffer Sourcing and Sinking Capability

Pin Name	Output Drive (Full AC Switching) Sourcing/Sinking Limits (mA)
	Sourcing	Sinking
All data, address, and I/O lines with clock doubler enabled	6.8	6.8

Under certain conditions, the maximum instantaneous AC/DC sourcing or sinking current may be greater than the limits outlined in Table A-7. The maximum AC/DC sourcing current can be as high as 12.5 mA per buffer as long as the number of sourcing buffers does not exceed three per V_DD or V_SS pad, or up to six outputs between pads. Similarly, the maximum AC/DC sinking current can be as high as 8.5 mA per buffer as long as the number of sinking buffers does not exceed three per V_DD or V_SS pad, or up to six outputs between pads. The V_DD bus can handle up to 35 mA, and the V_SS bus can handle up to 28 mA. All these analyses were measured at 100°C.

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.

Figure A-5. RCM3000 Areas Receiving Conformal Coating

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.

A.6 Jumper Configurations

Figure A-6 shows the header locations used to configure the various RCM3000 options via jumpers.

Figure A-6. Location of RCM3000 Configurable Positions

Table A-8 lists the configuration options.

Table A-8. RCM3000 Jumper Configurations

Header	Description	Pins Connected		Factory Default
JP1	Flash Memory Bank Select	1-2	Normal Mode	×
		2-3	Bank Mode
JP2	Flash Memory Size	1-2	128K/256K	×
		2-3	512K
JP3	Flash Memory Size	1-2	128K/256K	RCM3000
		2-3	512K
JP4	SRAM Size	1-2	128K	RCM3010
		2-3	512K	RCM3000
JP5	Auxiliary I/O data bus	1-2	Buffer disabled
		2-3	Buffer enabled	×

NOTE	The jumper connections are made using 0 W surface-mounted resistors.