User's Manual

LTE Module Series
EC21 Hardware Design
EC21_Hardware_Design Confidential / Released 27 / 94
control V
IL
max=0.6V
V
IH
min=1.2V
V
IH
max=2.0V
Pull-up by default.
In low voltage level,
module can enter into
airplane mode.
If unused, keep it
open.
AP_READY 2 DI
Application
processor sleep
state detection
V
IL
min=-0.3V
V
IL
max=0.6V
V
IH
min=1.2V
V
IH
max=2.0V
1.8V power domain.
If unused, keep it
open.
Other Interface Pins
Pin Name Pin No. I/O Description DC Characteristics Comment
USB_BOOT 115 DI
Force the module to
boot from USB port.
V
IL
min=-0.3V
V
IL
max=0.6V
V
IH
min=1.2V
V
IH
max=2.0V
1.8V power domain.
If unused, keep it
open.
RESERVED Pins
Pin Name Pin No. I/O Description DC Characteristics Comment
RESERVED
3, 18, 23,
28~34,
43, 55,
73~84,
113, 114,
116, 117,
140~144
Reserved
Keep these pins
unconnected.
1. “*” means under development.
2. Pads 24~27 are multiplexing pins used for audio design on EC21 module and BT function on FC20
module.
NOTES