I/O Buffer Sourcing And Sinking Limit - Rabbit RabbitCore RCM2200 User Manual

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
25.8 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–A12 and D1–D7
are each rated at 8 mA. The absolute maximum operating voltage on all I/O is V
or 5.5 V.
Table A-5 shows the AC and DC output drive limits of the parallel I/O buffers when the
Rabbit 2000 is used in the RCM2200.
Table A-5. I/O Buffer Sourcing and Sinking Capability
Pin Name
Output Port Name
PA [7:0]
PB [7:6]
PC [6, 2, 0]
PD [5:4]
**
PD [3:0]
PE [7, 5, 4, 1, 0]
* The maximum DC sourcing current for I/O buffers between V
pins is 112 mA.
† The maximum DC sinking current for I/O buffers between V
pins is 150 mA.
‡ The maximum DC output drive on I/O buffers must be adjusted to
take into consideration the current demands made my AC switch-
ing 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.
** The combined sourcing from Port D [7:0] may need to be adjusted
so as not to exceed the 112 mA sourcing limit requirement speci-
fied in Note 1.
User's Manual
Output Drive
*
Sourcing /Sinking
(mA)
Maximum
Full AC Switching
Drive
SRC/SNK
SRC/SNK
8/8 12/12
8/8 12/12
8/8 12/12
8/8 12/12
16/16 25/25
8/8 12/12
+ 0.5 V
DD
†
Limits
‡
DC Output
DD
SS
29