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6 ac characteristics, 1 symbol description, 2 ac characteristics measurement condition – Epson S1C33210 User Manual

Page 88

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8 ELECTRICAL CHARACTERISTICS

A-74

EPSON

S1C33210 PRODUCT PART

8.6 AC Characteristics

8.6.1 Symbol Description

t

CYC

: Bus-clock cycle time

• In x1 mode,

t

CYC

= 50 ns (20 MHz) when the CPU is operated with a 20-MHz clock

t

CYC

= 30 ns (33 MHz) when the CPU is operated with a 33-MHz clock

• In x2 mode,

t

CYC

= 50 ns (20 MHz) when the CPU is operated with a 40-MHz clock

t

CYC

= 40 ns (25 MHz) when the CPU is operated with a 50-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

V

IH

= V

DD

- 0.4 V

Low level

V

IL

= 0.4 V

Output signal High level

V

OH

= 1/2 V

DD

Low level

V

OL

= 1/2 V

DD

The following applies when OSC3 is external clock input:
Input signal

High level

V

IH

= 1/2 V

DD

Low level

V

IL

= 1/2 V

DD

Input signal waveform: Rise time (10%

90% V

DD

) 5 ns

Fall time (90%

10% V

DD

)

5 ns

Output load capacitance:

C

L

= 50 pF