Rabbit RabbitCore RCM3209, Руководство пользователя, Страница: 65 / 160

User’s Manual 59
A.2 Bus Loading
You must pay careful attention to bus loading when designing an interface to the
RCM3209/RCM3229. This section provides bus loading information for external devices.
Table A-2 lists the capacitance for the various RCM3209/RCM3229 I/O ports.
Table A-3 lists the external capacitive bus loading for the various RCM3209/RCM3229
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-2. 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-3. 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
44.2 100