I/O Buffer Sourcing And Sinking Limit; Bus Loading - Rabbit RabbitCore RCM5400W User Manual

C-programmable wi-fi core module

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A.3 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

100 MHz CPU clock with the clock doubler enabled 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 3.3 V ±10%.

A.4 Bus Loading

You must pay careful attention to bus loading when designing an interface to the

RCM5400W. This section provides bus loading information for external devices.

Table A-4 lists the capacitance for the various RCM5400W I/O ports.

Table A-4. Capacitance of Rabbit 5000 I/O Ports

Parallel Ports A to E

Table A-5 lists the external capacitive bus loading for the various RCM5400W 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-5.

Table A-5. External Capacitive Bus Loading -20°C to +85°C

Output Port

All I/O lines with clock

doubler enabled

OEM User's Manual

I/O Ports

Clock Speed

(MHz)

73.73

Input

Capacitance

(pF)

Maximum External

Capacitive Loading (pF)

100

Output

(pF)

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