ADSP-21369KSWZ-2A Datasheet, PDF (20/60 Pages) Analog Devices – SHARC Processors

ADSP-21367/ADSP-21368/ADSP-21369
Power-Up Sequencing
The timing requirements for processor start-up are given in
Table 12. Note that during power-up, a leakage current of
approximately 200μA may be observed on the RESET pin if it is
driven low before power up is complete. This leakage current
results from the weak internal pull-up resistor on this pin being
enabled during power-up.
Table 12. Power-Up Sequencing Timing Requirements (Processor Start-up)
Parameter
Min
Max
Unit
Timing Requirements
t_RSTVDD
RESET Low Before V /V _{DDINT DDEXT} On
0
t_IVDDEVDD
V_DDINT On Before V_DDEXT
–50
t1
CLKVDD
CLKIN Valid After V /V _{DDINT DDEXT} Valid
0
t_CLKRST
CLKIN Valid Before RESET Deasserted
10²
t_PLLRST
PLL Control Setup Before RESET Deasserted
20
Switching Characteristic
ns
+200 ms
200
ms
μs
μs
t_CORERST
Core Reset Deasserted After RESET Deasserted
4096t_CK + 2 t_CCLK ^{3, 4}
1 _{Valid V /V DDINT DDEXT assumes that the supplies are fully ramped to their 1.2 V rails and 3.3 V 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 start-up timing of crystal oscillators. Refer to your crystal oscillator manufacturer’s data sheet for start-up time.}
Assume a 25 ms maximum oscillator start-up time if using the XTAL pin and internal oscillator circuit in conjunction with an external crystal.
3 _{Applies after the power-up sequence is complete. Subsequent resets require RESET to be held low a minimum of four CLKIN cycles in order to properly initialize and propagate}
default states at all I/O pins.
4 _{The 4096 cycle count depends on tsrst specification in Table 14. If setup time is not met, 1 additional CLKIN cycle may be added to the core reset time, resulting in 4097 cycles}
maximum.
RESET
V_DDINT
V_DDEXT
CLKIN
CLK_CFG1–0
RESETOUT
t_RSTVDD
t_IVDDEVDD
t_CLKVDD
t_CLKRST
t_PLLRST
t_CORERST
Figure 6. Power-Up Sequencing
Rev. E | Page 20 of 60 | July 2009