N723-EA Hardware User Guide
Chapter 5 Application Interfaces
Copyright © Neoway Technology Co., Ltd. All rights reserved.
60
5.7
Multi-Function Interfaces
Table 5-2
Pin definition description
Pin
Function (default)
Multiplexed function 1
Remarks
9
I2S_SCLK
PCM_CLK
-
10
I2S_TX
PCM_DOUT
-
11
I2S_RX
PCM_DIN
-
12
I2S_WS
PCM_SYNC
-
If you need to multiplex the pin function, ensure that the firmware supports multiplexing; for details, consult
Neoway FAEs.
5.8
Other Interfaces
Signal
Pin
I/O
Function description
Remarks
RING
13
DO
Incoming call indicator control
-
NET_LIGHT
83
DO
Network indicator control
-
5.8.1
RING
⚫
RING indicator for an incoming call
Once a voice call is incoming, the UART port outputs "RING" character strings and meanwhile
the RING pin outputs a negative pulse with a width of 30 ms and a period of 5 seconds. After the
call is answered, the pin restores to high-level output.
Figure 5-40
Pulse wave for an incoming call
5 s
30 ms
30 ms