Bus Loading - Rabbit RabbitCore RCM3305 User Manual

A.2 Bus Loading
You must pay careful attention to bus loading when designing an interface to the
RCM3305/RCM3315. This section provides bus loading information for external devices.
Table A-2 lists the capacitance for the various RCM3305/RCM3315 I/O ports.
Table A-2. Capacitance of Rabbit 3000 I/O Ports
Parallel Ports A to G
Table A-3 lists the external capacitive bus loading for the various RCM3305/RCM3315
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-3.
Table A-3. External Capacitive Bus Loading -40°C to +85°C
Output Port
All I/O lines with clock
doubler enabled
User's Manual
I/O Ports
Clock Speed
(MHz)
44.2
Input
Capacitance Capacitance
(pF)
12
Maximum External
Capacitive Loading (pF)
100
Output
(pF)
14
71