20-668-0024 Rabbit Semiconductor, 20-668-0024 Datasheet - Page 258

• Manufacturer Part Number: 20-668-0024
• Description: IC CPU RABBIT4000 128-LQFP
• Manufacturer: Rabbit Semiconductor

Specifications of 20-668-0024

• Processor Type: Rabbit 4000 8-bit
• Speed: 60MHz
• Voltage: 2.5V, 2.7V, 3V, 3.3V
• Mounting Type: Surface Mount
• Package / Case: 128-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Other names: 20-668-0022; 316-1078

24.1.2 I/O Strobes
There are eight I/O strobes available in the Rabbit 4000. Each has a separate 8KB address
range that can be enabled as a chip select, read strobe, write strobe, or a read/write strobe.
The number of wait states can be set to 1, 3, 7, or 15, and the signal can be active high or
low.
The I/O strobes can be used for devices on the memory bus or the auxiliary I/O bus, and
can be enabled to go out on the memory bus alone or both buses. It is also possible to
shorten the read strobe by one clock cycle and the write strobe by one-half a clock cycle
by pulling in the trailing edge, which guarantees one clock cycle of hold time for transac-
tions.
248
Register
Figure 24-1. Auxiliary I/O Bus Cycles
IB0CR
IB1CR
IB2CR
IB3CR
IB4CR
IB5CR
IB6CR
IB7CR
Table 24-1. External I/O Strobes
External I/O Address Range
0xA000–0xBFFF
0xC000–0xDFFF
0xE000–0xFFFF
0x0000–0x1FFF
0x2000–0x3FFF
0x4000–0x5FFF
0x6000–0x7FFF
0x8000–0x9FFF
Rabbit 4000 Microprocessor User’s Manual