ADSP-21375KSZ-ENG 查看數據表（PDF） - Analog Devices

零件编号

产品描述 (功能)

生产厂家

ADSP-21375KSZ-ENG

SHARC® Processor

Analog Devices 

Preliminary Technical Data

ADSP-21375

Power-Up Sequencing

The timing requirements for processor startup are given in

Table 11.

Table 11. Power Up Sequencing Timing Requirements (Processor Startup)

Parameter

Min

Timing Requirements

tRSTVDD

RESET Low Before VDDINT/VDDEXT On

0

tIVDDEVDD

VDDINT on Before VDDEXT

–50

tCLKVDD1

CLKIN Valid After VDDINT/VDDEXT Valid

0

tCLKRST

CLKIN Valid Before RESET Deasserted

102

tPLLRST

PLL Control Setup Before RESET Deasserted

203

Max

Unit

ns

200

ms

200

ms

μs

μs

Switching Characteristic

tCORERST

Core Reset Deasserted After RESET Deasserted

4096tCK + 2 tCCLK 4, 5

1 Valid VDDINT/VDDEXT assumes that the supplies are fully ramped to their 1.2 and 3.3 volt rails. Voltage ramp rates can vary from microseconds to hundreds of milliseconds

depending on the design of the power supply subsystem.

2 Assumes a stable CLKIN signal, after meeting worst-case startup timing of crystal oscillators. Refer to your crystal oscillator manufacturer's datasheet for startup time.

Assume a 25 ms maximum oscillator startup time if using the XTAL pin and internal oscillator circuit in conjunction with an external crystal.

3 Based on CLKIN cycles

4 Applies after the power-up sequence is complete. Subsequent resets require a minimum of four CLKIN cycles for RESET to be held low in order to properly initialize and

propagate default states at all I/O pins.

5 The 4096 cycle count depends on tSRST specification in Table 13. If setup time is not met, one additional CLKIN cycle may be added to the core reset time, resulting in

4097 cycles maximum.

RESET

VDDINT

VDDEXT

CLKIN

CLK_CFG1-0

RSTOUT

tRSTVDD

tIVDDEVDD

tCLKVDD

tCLKRST

tPLLRST

Figure 3. Power-Up Sequencing

tCO RERST

Rev. PrB | Page 19 of 42 | December 2005

Share Link: