Appendix A. RabbitCore RCM2300 Specifications

Appendix A provides the specifications for the RCM2300, and describes the conformal coating.

A.1 Electrical and Mechanical Characteristics

Figure A-1 shows the mechanical dimensions for the RCM2300.

Figure A-1. RabbitCore RCM2300 Dimensions

Table A-1 provides the pin 1 locations for the RCM2300 headers viewed from the top side (as in Figure A-1).

Table A-1. RabbitCore RCM2300 Header Pin 1 Locations

Header	Description	Pin 1 (x,y) Coordinates (Inches)
J4	RabbitCore RCM2300 user board interface	(0.100, 1.445)
J5	RabbitCore RCM2300 user board interface	(0.100, 0.195)
J1	Programming header (top side)	(0.125, 1.515)
Top GND	Through-Hole Connection Points	(1.110, 1.560)

Table A-2 lists the electrical, mechanical, and environmental specifications for the RCM2300.

Table A-2. RabbitCore RCM2300 Specifications 

Parameter	Specification
Board Size	1.15" × 1.60" × 0.48" (29 mm × 41 mm × 12 mm)
Operating Temperature	-40°C to +70°C
Humidity	5% to 95%, noncondensing
Input Voltage	4.75 V to 5.25 V DC
Current	108 mA at 22.1 MHz, 5 V DC; 10 mA additional with programming cable attached
General-Purpose I/O1	29 parallel I/0 lines grouped in five 8-bit ports (shared with serial ports): 17 configurable I/O, 8 fixed inputs, 4 fixed outputs
Memory, I/O Interface	4 address lines, 8 data lines, I/O read/write
Additional Digital Inputs	Startup mode (2), reset in
Additional Digital Outputs	Status, reset out
Microprocessor	Rabbit 2000TM
Clock	22.1 MHz
SRAM	128K × 8, surface mount
Flash Memory	One 256K × 8, surface mount
Timers	Five 8-bit timers cascadable in pairs, one 10-bit timer with 2 match registers that each have an interrupt
Serial Ports	Four CMOS-compatible ports; two ports are configurable as clocked ports.
Serial Rate	Maximum sustained synchronous rate of 2.76 Mbps or asynchronous rate of 345,600 bps
Slave Interface	A slave port allows the RCM2300 to be used as an intelligent peripheral device slaved to a master processor, which may either be another Rabbit 2000 or any other type of processor
Program/Debug	One clock line is available only on the programming header. The programming port is available both on the programming header (J1) and on J4, one of the headers that inetrfaces with the user board
Watchdog/Supervisor	Yes
Time/Date Clock	Yes
Socket Strip (for connection to headers J4 and J5)	2x13, 2 mm pitch
Backup Battery	Provision for user-supplied backup battery (2.85 V to 3.15 V) via connections on header J5

1 11 additional I/O are available via less convenient 0.30" diameter through-hole connection points

A.1.1 Headers

The RCM2300 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-2 shows the footprint of another board that the RCM2300 would be plugged into. These values are relative to the header connectors.

Figure A-2. User Board Footprint for RabbitCore RCM2300

A.1.2 Physical Mounting

An insulating 9/32" or ¼" (7 mm) standoff with a 4-40 screw is recommended to attach the RCM2300 to a user board at the hole position shown in Figure A-2.

A.2 Bus Loading

You must pay careful attention to bus loading when designing an interface to the RCM2300. This section provides bus loading information for external devices.

Table A-3 lists the capacitance for the various Rabbit 2000 I/O ports with SRAM and flash memory connected.

Table A-3. Capacitance of Rabbit 2000 I/O Ports with External Memory

I/O Ports	Input Capacitance (pF)	Output Capacitance (pF)
Parallel Ports A to E	12	14
Data Lines D0-D7	30	32
Address Lines A0-A12	--	32

Table A-4 lists the external capacitive bus loading for the various Rabbit 2000 output ports. Be sure to add the loads for the devices you are using in your system and verify that they do not exceed the values in Table A-4.

Table A-4. External Capacitive Bus Loading -40°C to +85°C

Output Port	Clock Speed (MHz)	Maximum External Capacitive Loading (pF)
A[4:1] D[7:1]	22.1	50
A[4:1] D[7:1]	22.1	100 for 55 ns flash
A0 D0	22.1	100
PD[3:0]	22.1	100
PA[7:0] PB[7,6] PC[6,2,0] PD[7:0] PE[7:0]	22.1	90
All data, address, and I/O lines with clock doubler disabled	11.06	100

The values from the table above are derived using 55 ns (flash memory) and 70 ns (SRAM) memory access times. External capacitive loading can be improved by 10 pF for commercial temperature ranges, but do not exceed 100 pF. See the AC timing specifications in the Rabbit 2000 Users Manual for more information.

Figure A-3 shows a typical timing diagram for the Rabbit 2000 microprocessor external memory read and write cycles.

Figure A-3. 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-5 lists the parameters shown in these figures and provides minimum or measured values.

Table A-5. Memory and External I/O Read/Write Parameters

Parameter		Description	Value
Read Parameters	Tadr	Time from CPU clock rising edge to address valid	Max.	7 ns @ 20 pF, 5 V (10 ns @ 3.3 V) 14 ns @ 70 pF, 5 V (19 ns @ 3.3 V)
	Tsetup	Data read setup time	Min.	2 ns @ 5 V (3 ns @ 3.3 V)
	Thold	Data read hold time	Min.	0 ns
Write Parameters	Tadr	Time from CPU clock rising edge to address valid	Max.	7 ns @ 20 pF, 5 V (10 ns @ 3.3 V) 14 ns @ 70 pF, 5 V (19 ns @ 3.3 V)
	Thold	Data write hold time from /WEx or /IOWR	Min.	½ CPU clock cycle

A.3 Rabbit 2000 DC Characteristics

Table A-6 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-6. 5.0 Volt DC Characteristics

Symbol	Parameter	Test Conditions	Min	Typ	Max	Units
IIH	Input Leakage High	VIN = VDD, VDD = 5.5 V			10	µA
IIL	Input Leakage Low (no pull-up)	VIN = VSS, VDD = 5.5 V	-10			µA
IOZ	Output Leakage (no pull-up)	VIN = VDD or VSS, VDD = 5.5 V	-10		10	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 = 5.0 V, 25°C		2.4		V
VOL	CMOS Output Low Voltage	IOL = See Table A-7 (sinking) VDD = 4.5 V		0.2	0.4	V
VOH	CMOS Output High Voltage	IOH = See Table A-7 (sourcing) VDD = 4.5 V	0.7 x VDD	4.2		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 22.1 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-A4 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-7 shows the AC and DC output drive limits of the parallel I/O buffers when the Rabbit 2000 is used in the RCM2300.

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

Pin Name	Output Drive Sourcing1/Sinking2 Limits (mA)
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 [7::4]	8/8	12/12
PD [3:0]4	16/16	25/25
PE [7:0]	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 area around the crystal oscillator has had the Dow Corning silicone-based 1-2620 conformal coating applied. The conformally coated area is shown in Figure A-4. The conformal coating protects these high-impedance circuits from the effects of moisture and contaminants over time.

Figure A-4. RCM2300 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 Rabbit Semiconductor Technical Note 303, Conformal Coatings.