8 ELECTRICAL CHARACTERISTICS

8.6 AC Characteristics

8.6.1 Symbol Description

tCYC: Bus-clock cycle time

•In x1 mode, tCYC = 50 ns (20 MHz) when the CPU is operated with a 20-MHz clock tCYC = 30 ns (33 MHz) when the CPU is operated with a 33-MHz clock

•In x2 mode, tCYC = 50 ns (20 MHz) when the CPU is operated with a 40-MHz clock tCYC = 40 ns (25 MHz) when the CPU is operated with a 50-MHz clock tCYC = 33 ns (30 MHz) when the CPU is operated with a 60-MHz clock

WC: Number of wait cycles

Up to 7 cycles can be set for the number of cycles using the BCU control register. Furthermore, it can be extended to a desired number of cycles by setting the #WAIT pin from outside of the IC.

The minimum number of read cycles with no wait (0) inserted is 1 cycle.

The minimum number of write cycles with no wait cycle (0) inserted is 2 cycles. It does not change even if 1-wait cycle is set. The write cycle is actually extended when 2 or more wait cycles are set.

When inserting wait cycles by controlling the #WAIT pin from outside of the IC, pay attention to the timing of the #WAIT signal sampling. Read cycles are terminated at the cycle in which the #WAIT signal is negated. Write cycles are terminated at the following cycle after the #WAIT signal is negated.

C1, C2, C3, Cn: Cycle number

C1 indicates the first cycle when the BCU transfers data from/to an external memory or another device. Similarly, C2 and Cn indicate the second cycle and nth cycle, respectively.

Cw: Wait cycle

Indicates that the cycle is wait cycle inserted.

8.6.2 AC Characteristics Measurement Condition

Signal detection level: Input signal

High level

VIH = VDDE - 0.4 V

 

Low level

VIL = 0.4 V

Output signal

High level

VOH = 1/2 VDDE

 

Low level

VOL = 1/2 VDDE

The following applies when OSC3 is external clock input:

Input signal

High level

VIH = 1/2 VDD

 

Low level

VIL = 1/2 VDD

Input signal waveform: Rise time (10% →

90% VDD)

5 ns

Fall time (90% →

10% VDD)

5 ns

Output load capacitance: CL = 50 pF

 

 

A-78

EPSON

S1C33L03 PRODUCT PART