Product Info

Wi-Fi&BT Module Series
FC21 Hardware Design
FC21_Hardware_Design 18 / 52
1.
1)
indicates that SDIO_D2 is a boot strap signal, which must be kept at high level for normal
operation during power on.
2.
2)
indicates that 32KHz_IN is reserved on FC21 module since the sleep function is still to be
developed.
pin open.
LTE_UART_
RXD
6 DI
LTE/Wi-Fi&BT
coexistence signal
V
IL
min=-0.3V
V
IL
max=0.54V
V
IH
min=1.26V
V
IH
max=2.0V
1.8V power domain.
If unused, keep this
pin open.
RF Interface
Pin Name Pin No. I/O Description DC Characteristics Comment
RF_ANT 30 IO
Wi-Fi/BT antenna
interface
50Ω impedance.
Other Interfaces
Pin Name Pin No. I/O Description DC Characteristics Comment
DBG_TXD 4 OD
Used for software
debugging
V
OL
max=0.18V
V
OH
min=1.62V
1.8V power domain.
Require external pull-
up to 1.8V.
If unused, keep this pin
open.
32KHz_IN
2)
19 DI
Low power.
External 32.768kHz
clock input.
V
IL
min=-0.3V
V
IL
max=0.54V
V
IH
min=1.26V
V
IH
max=2.0V
1.8V power domain.
If unused, keep this pin
open.
RESERVED Pins
Pin Name Pin No. I/O Description DC Characteristics Comment
RESERVED
2, 3,
33~35,
37, 41,
42, 47
Reserved
Keep these pins
open.
NOTES