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APPENDIX B. RABBIT 2000 REVISIONS
B.1 Rabbit 2000 Revisions
Since its release, the Rabbit 2000 microprocessor has gone through a number of revisions.
The revisions reflect bug fixes, improvements, and the introduction of new features. All
Rabbit 2000 revisions are pin-compatible and transparently replace previous versions of
the chip.
The Rabbit 2000 has been supplied in the following versions.
1. Original Rabbit 2000—identified by IQ2T on the package. This original Rabbit 2000
began shipping in November,1999, and was phased out in January, 2002. There were
several bugs:
(a) Certain instructions did not function correctly as described in Technical Note
TN302, Rabbit 2000 Instruction Bug. The Dynamic C compiler corrects this
situation automatically.
(b) The external interrupt inputs had to be tied together with a resistor as described
in Technical Note TN301, Rabbit 2000 Microprocessor Interrupt Problem.
(c) Wait states did not function properly when used to access code in slower mem-
ories because certain instructions failed in these circumstances. This bug is
fixed in the Rabbit 2000A through Rabbit 2000C revisions.
2. First revision (Rabbit 2000A)—identified by IQ3T on the package. This version
began shipping in January, 2002. All the bugs in the original Rabbit 2000 were fixed,
and additional new features were added:
(a) Support for separate I & D space.
(b) An additional register in the serial port hardware simplifies sending out an
additional stop bit or parity bit.
(c) Improvements in the battery-backup hardware allow for implementation of a
simplified circuit for backing up the real-time clock and associated static
RAM. A new bug exists in the block copy instruction between separate I & D
spaces that is only active when the separate I & D space is enabled. This bug is
automatically corrected by Dynamic C.