668-0003-C Rabbit Semiconductor, 668-0003-C Datasheet - Page 160

• Manufacturer Part Number: 668-0003-C
• Description: IC CPU RABBIT2000 30MHZ 100PQFP
• Manufacturer: Rabbit Semiconductor

Specifications of 668-0003-C

• Rohs Status: RoHS non-compliant
• Processor Type: Rabbit 2000 8-Bit
• Speed: 30MHz
• Voltage: 2.7V, 3V, 3.3V, 5V
• Mounting Type: Surface Mount
• Package / Case: 100-MQFP, 100-PQFP
• Features: -
• Other names: 316-1004; 668-0003

15.1 Memory Access and I/O Read/Write Times
The memory access time requirements are listed in Table 15-2. It is important that wait
states should not be used for any memory that holds code that is being executed. Memory
wait states are only intended for use with data accesses. For code memory the clock should
be matched to the memory requirements, or one of the clock dividers should be enabled to
accommodate slow memory. As a rough guide, each data memory wait state in main RAM
that is introduced will reduce the average compute performance by approximately 8%.
The data memory read access is slowed by 50% for 1 wait state and is slowed by 100% for
2 wait states. However, since only a small proportion of accesses are data accesses rather
than code accesses or instruction fetch cycles, the overall affect on performance is slight.
If data memory wait states are introduced, it is important to use the macros specified in the
BIOS so that the compiler will be aware of the wait states.
Generally, the maximum operating speed is proportional to the power supply voltage. The
operating current is proportional to the voltage, and so the operating power is proportional
to the square of the voltage. The operating power is also proportional to the clock speed.
Higher temperatures reduce the maximum operating speed by approximately 1% for each
5°C. In addition, higher operating speeds increase the die temperature because of the heat
generated and therefore slightly compound the adverse effects of higher temperature.
154
Rabbit 2000 Microprocessor User’s Manual