LPWA Module Series
BG77 Hardware Design
BG77_Hardware_Design 43 / 76
The following figure shows a reference design of PCM and I2C interfaces with an external codec IC.
PCM_DIN
PCM_SYNC
PCM_CLK
I2C_SCL
I2C_SDA
Module
1.8V
4.7K
4.7K
BCLK
WCLK
ADC
SCL
SDA
BIA
S
MICBIAS
INP
INN
LOUTP
LOUTN
Codec
PCM_DOUT
DAC
Figure 19: Reference Circuit of PCM Application with Audio Codec
“*” means under development.
3.13. Network Status Indication
BG77 provides one network status indication pin: NETLIGHT. The pin is used to drive a network status
indication LED. The following tables describe the pin definition and logic level changes of NETLIGHT in
different network activity status.
Table 17: Pin Definition of NETLIGHT
Table 18: Working State of NETLIGHT
Pin Name
Pin No.
I/O
Description
Comment
NETLIGHT 79 DO
Indicate
the
module’s network activity status
BOOT_CONFIG.
Do not pull it up
before startup.
1.8V power domain.
Pin Name
Logic Level Changes
Network Status
NOTE