ADSP-21266SKBC-2B AD [Analog Devices], ADSP-21266SKBC-2B Datasheet - Page 18

• Manufacturer Part Number: ADSP-21266SKBC-2B
• Description: SHARC Embedded Processor
• Manufacturer: AD [Analog Devices]

ADSP-21266
Power-Up Sequencing
The timing requirements for DSP startup are given in
and
Table 10. Power-Up Sequencing (DSP Startup)
1
2
3
4
5
Parameter
Timing Requirements
t
t
t
t
t
Switching Characteristic
t
Valid V
Assumes a stable CLKIN signal, after meeting worst-case startup timing of crystal oscillators. Refer to the crystal oscillator manufacturer’s data sheet for startup time.
Based on CLKIN cycles.
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
The 4096 cycle count depends on t
RSTVDD
IVDDEVDD
CLKVDD
CLKRST
PLLRST
CORERST
depending on the design of the power supply subsystem.
Assume a 25 ms maximum oscillator startup time if using the XTAL pin and internal oscillator circuit in conjunction with an external crystal.
propagate default states at all I/O pins.
4097 cycles maximum.
Figure
DDINT
/V
6.
DDEXT
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
CLK_CFG1–0
RESET Low Before V
V
CLKIN Valid After V
CLKIN Valid Before RESET Deasserted
PLL Control Setup Before RESET Deasserted
DSP Core Reset Deasserted After RESET Deasserted
V DDEXT
RSTOUT
V DDINT
DDINT
RESET
CLKIN
SRST
On Before V
*
*
specification in
MULTIPLEXED WITH CLKOUT
t
RSTVDD
DDEXT
DDINT
DDINT
Table
/V
/V
DDEXT
DDEXT
12. If setup time is not met, one additional CLKIN cycle may be added to the core reset time, resulting in
Rev. B | Page 18 of 44 | May 2005
Valid
Figure 6. Power-Up Sequencing
On
Table 10
1
t
IVDDEVDD
t
PLLRST
t
t
CLKVDD
CLKRST
Min
0
–50
0
10
20
4096t
t
2
3
CORERST
CK
4, 5
Max
200
200
Unit
ns
ms
ms
µs
µs