Rabbit 6000 User’s Manual
digi.com
350
By default the I/O strobes are configured as read-only chip selects with 15 wait states and normal timing.
These settings will affect the /IORD, /IOWR, and /BUFEN signals for external I/O writes even if no other
strobe outputs are enabled in the parallel port registers.
The most common configuration of the I/O strobes is to use them a chip select signals for external devices
that share /IORD and /IOWR for the read and write strobes.
31.1.3 I/O Handshake
An external I/O handshake input can be enabled on one of the Parallel Port E pins for any combination of
the I/O banks. The external device holds this signal (active high or low) when it is busy and cannot accept
a transaction. The Rabbit 6000 will then hold midway through the transaction until either the handshake
signal goes inactive or a timeout occurs. The timeout can be defined anywhere from 32 to 2048 clocks.
When the timeout occurs, the transaction ends and a status bit is set. This bit must be checked by the pro-
gram attempting the write; no interrupt is generated.
The I/O handshake signal is sampled at the end of the first wait state (Tw). When the handshake signal is
disabled, the transition will start at the beginning of the Tw phase and continue to completion.
Figure 31.2 External I/O Handshake Timing Diagram
Summary of Contents for 6000
Page 1: ...Rabbit 6000 Microprocessor User s Manual 90001108_J...
Page 11: ...Rabbit 6000 User s Manual digi com 11 1 3 Block Diagram Figure 1 1 Rabbit 6000 Block Diagram...
Page 43: ...Rabbit 6000 User s Manual digi com 43 4 1 1 Block Diagram...
Page 57: ...Rabbit 6000 User s Manual digi com 57 5 1 1 Block Diagram...
Page 88: ...Rabbit 6000 User s Manual digi com 88 7 2 Block Diagram...
Page 115: ...Rabbit 6000 User s Manual digi com 115 11 1 1 Block Diagram...
Page 127: ...Rabbit 6000 User s Manual digi com 127 12 1 1 Block Diagram...
Page 138: ...Rabbit 6000 User s Manual digi com 138 13 1 1 Block Diagram...
Page 154: ...Rabbit 6000 User s Manual digi com 154 15 1 1 Block Diagram...
Page 163: ...Rabbit 6000 User s Manual digi com 163 16 1 1 Block Diagram...
Page 170: ...Rabbit 6000 User s Manual digi com 170 17 1 1 Block Diagram...
Page 177: ...Rabbit 6000 User s Manual digi com 177 18 1 1 Block Diagram...
Page 186: ...Rabbit 6000 User s Manual digi com 186 19 1 1 Block Diagram...
Page 230: ...Rabbit 6000 User s Manual digi com 230 22 2 Block Diagram...
Page 234: ...Rabbit 6000 User s Manual digi com 234 Figure 22 3 Sample Slow A D Converter Circuit...
Page 287: ...Rabbit 6000 User s Manual digi com 287 25 1 1 Block Diagram...
Page 310: ...Rabbit 6000 User s Manual digi com 310 26 1 1 Block Diagram...
Page 323: ...Rabbit 6000 User s Manual digi com 323 28 1 1 Block Diagram...
Page 351: ...Rabbit 6000 User s Manual digi com 351 31 1 4 Block Diagram...
Page 361: ...Rabbit 6000 User s Manual digi com 361 32 1 1 Block Diagram...
Page 369: ...Rabbit 6000 User s Manual digi com 369 33 2 Block Diagram...
Page 390: ...Rabbit 6000 User s Manual digi com 390 35 1 1 Block Diagram...
Page 408: ...Rabbit 6000 User s Manual digi com 408...
Page 410: ...Rabbit 6000 User s Manual digi com 410...
Page 411: ...Rabbit 6000 User s Manual digi com 411...
Page 420: ...Rabbit 6000 User s Manual digi com 420 Figure 37 1 Memory Read and Write Cycles...