Datasheet
QuickLogic EOS S3 Ultra Low Power multicore MCU datasheet - Version 3.3d  27-129 
© 2020 QuickLogic Corporation   
www.quicklogic.com  72
 Power-On Sequence of Crystal Clock 
The recommended power-on  sequence of  the EOS S3 when crystal  clock is used as input to XTAL_IN  is  shown  in  the 
following figure.
Figure 46: Power-On Sequence of Crystal Clock 
XTAL_IN
XTAL_OUT
PAD(8) [Pull Down]
PAD(9) [Pull Down]
32.768 kHz 
Clock
Host_SPI_Access Start
Host SPI (AP) Access
SYS_RSTn
CRYSTAL IN
VCCIO
LDO_VIN/VDD1/VDD2
AVDD
500 ms (Min.)
Reset during middle of operation
300 µs (Min.)
300 µs 
(Min.)
2 ms 
(Max.)
Boot Strap Pins
Boot Value
1 µs 
(Min)
1 µs 
(Min)
Do Not Care
Do Not Care
XTAL_IN
Chip ready 2 ms after 
SYS_RSTn release
2 ms
G
The following figure shows the power-on sequence timing parameters. 










