Jameco Electronics 2000 manual Appendix B. Rabbit 3000 Revisions

APPENDIX B. RABBIT 3000 REVISIONS

Since its release, the Rabbit 3000 microprocessor has gone through one revision. The revi- sion reflects bug fixes, improvements, and the introduction of new features. All Rabbit 3000 revisions are pin-compatible, and transparently replace previous versions of the chip.

The Rabbit 3000 has been supplied in the following versions.

1.Original Rabbit 3000—Available in two packages and identified by IL1T for the LQFP package and IZ1T for the TFBGA package. The LQFP package began shipping in March 2002, and the TFBGA package began shipping in January 2003. There were several bugs:

(a)Port A decode bug—This bug is documented in TN228, Rabbit 3000 Parallel Port F Bug. The problem involves an incomplete address decode of the data output register for Parallel Port A. If Parallel Port A is used as an output or is used as the bidirectional bus for the slave port, then writing to any of the Paral- lel Port F registers will cause a spurious write to the Parallel Port A register.

(b)LDIR/LDDR with wait states—This bug is documented in Section 19.16. The nature of the problem is such that first iteration of LDIR/LDDR uses the cor- rect number of wait states for both the read and the write. However, all subse- quent iterations use the number of waits programmed for the memory located at the write address for both the read and the write cycles. This becomes a problem when moving a block of data from a slow memory device requiring wait states to a fast memory device requiring no wait states.

(c)Interrupt after I/O with Short /CSx enabled—This bug is documented in Section 7.5. When the short chip select option is enabled, the interrupt sequence will attempt to write the return address to the stack if an interrupt takes place immediately after an internal or an external I/O instruction. The chip select will be suppressed during the write cycle, and the correct return address will not be stored on the stack. This happens only when an interrupt takes place immediately after an I/O instruction when the short chip select option is enabled.

(d)IrDA bug—This bug is documented in TN236, Rabbit 3000 IrDA Bug. When configured to operate in the IrDA mode, the serial port may at times generate an extra pulse before the start bit is transmitted. This pulse may appear either before a multi-character transmission or before a single-character transmission. If the beginning of the start bit coincides with when the IrDA pulse generator output is high, there will be a spurious 1/16th-bit cell pulse on the transmit output.

User’s Manual 273