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
BIAS
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
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