Cypress CY8C21634 用户手册

Document Number: 38-12025  Rev. *O

Page 31 of 45

 lists the guaranteed maximum and minimum specifications for the voltage and temperature ranges: 4.75V to 5.25V and -40°C

≤ T

A

 

≤ 85°C, or 3.0V to 3.6V and -40°C ≤ T

A

 

≤ 85°C, respectively. Typical parameters apply to 5V, 3.3V, or 2.7V at 25°C and are for

design guidance only.

F

OSCEXT

Frequency with CPU Clock divide by 1

0.093

–

12.3

MHz

Maximum CPU frequency is 12 

MHz at 3.3V. With the CPU clock 

divider set to 1, the external clock 

must adhere to the maximum 

frequency and duty cycle 

requirements.

F

OSCEXT

Frequency with CPU Clock divide by 2 or 

greater

0.186

–

24.6

MHz

If the frequency of the external clock 

is greater than 12 MHz, the CPU 

clock divider must be set to 2 or 

greater. In this case, the CPU clock 

divider ensures that the fifty percent 

duty cycle requirement is met.

–

High Period with CPU Clock divide by 1

41.7

–

5300

ns

–

Low Period with CPU Clock divide by 1

41.7

–

–

ns

–

Power Up IMO to Switch

150

–

–

μs

F

OSCEXT

Frequency with CPU Clock divide by 1

0.093

–

3.08

0

MHz

Maximum CPU frequency is 3 MHz 

at 2.7V. With the CPU clock divider 

set to 1, the external clock must 

adhere to the maximum frequency 

and duty cycle requirements.

F

OSCEXT

Frequency with CPU Clock divide by 2 or 

greater

0.186

–

6.35

MHz

If the frequency of the external clock 

is greater than 3 MHz, the CPU 

clock divider must be set to 2 or 

greater. In this case, the CPU clock 

divider ensures that the fifty percent 

duty cycle requirement is met.

–

High Period with CPU Clock divide by 1

160

–

5300

ns

–

Low Period with CPU Clock divide by 1

160

–

–

ns

–

Power Up IMO to Switch

150

–

–

μs

T

RSCLK

Rise Time of SCLK 

1

–

20

ns

T

FSCLK

Fall Time of SCLK 

1

–

20

ns

T

SSCLK

Data Set up Time to Falling Edge of SCLK

40

–

–

ns

T

HSCLK

Data Hold Time from Falling Edge of SCLK

40

–

–

ns

F

SCLK

Frequency of SCLK

0

–

8

MHz

T

ERASEB

Flash Erase Time (Block)

–

15

–

ms