1.1 Interface Description

The following figure illustrates the pin diagram of the BM20 module.

Figure 1-3. BM20 Module Pin Diagram

The following table provides the pin description of the BM20 module.

Table 1-1. BM20 Module Pin Description
Pin No. Name Pin type Description
1 P0_0 I/O

I/O pin, default pull-high input (Note 1)

  • Slide switch detector, active-low
  • UART TX_IND, active-low
2 EAN I

Embedded ROM/External Flash enable

H: Embedded; L: External Flash
3 P3_0 I

I/O pin, default pull-high input (Note 1)

Line-in Detector (default), active-low
4 P2_0 I

I/O pin, default pull-high input

System Configuration,

H: Application L: Base band (Test Mode)
5 P1_5 I/O

I/O pin, default pull-high input (Note 1)

  • NFC detection pin, active low
  • Out_Ind_0
  • Slide Switch Detector, active low
  • Buzzer Signal Output
6 P0_4 I/O

I/O pin, default pull-high input (Note 1)

  • NFC detection pin, active low
  • Out_Ind_0
7 SPKR O Right-channel, analog headphone output
8 AOHPM O Headphone common mode output/sense input
9 SPKL O Left-channel, analog headphone output
10 VDDA P Positive power supply/reference voltage for Codec, no need to add power to this pin
11 MIC1_P I MIC 1 mono differential analog positive input
12 MIC1_N I MIC 1 mono differential analog negative input
13 MIC_BIAS P Electric microphone biasing voltage
14 AIR I Right-channel, single-ended analog input
15 AIL I Left-channel, single-ended analog input
16 RST I System Reset pin, Low: reset
17 VCC_RF P 1.28V RF LDO output, no need to add power to this pin
18 P0_1 I/O

I/O pin, default pull-high input (Note 1)

  • FWD key, when Class 2 RF (default), active-low
  • Class 1 TX Control signal of external RF T/R switch, active-high
19 VDD_IO P Power output, no need to add power to this pin
20 ADAP_IN P 5V Power adapter input
21 BAT_IN P 3.0V to 4.2V Li-Ion battery input
22 NC — No connection
23 GND P Ground pin
24 SYS_PWR P

System power output

BAT mode: 3.0 to 4.2V

Adapter mode: 4.0V
25 BK_OUT P 1.8V Buck output, no need to add power to this pin
26 MFB I
  • Power key in off mode
  • UART_RX_IND: MCU used to wake-up Bluetooth® (Note 1)
27 LED1 I LED driver 1
28 LED2 I LED driver 2
29 P2_4 I

I/O pin, default pull-high input

System Configuration

L: Boot Mode with P2_0 low combination
30 P0_2 I

I/O pin, default pull-high input (Note 1)

Play/Pause key (default), active-low
31 P0_3 I/O

I/O pin, default pull-high input (Note 1)

  • REV key (default), active low
  • Buzzer Signal Output
  • Out_Ind_1
  • Class 1 RX control signal of external RF T/R switch, active-high
32 HCI_TXD O HCI-UART data output
33 HCI_RXD I HCI-UART data input
34 P0_5 I

I/O pin, default pull-high input (Note 1)

Volume down (default), active-low
35 P2_7 I

I/O pin, default pull-high input (Note 1)

Volume up key (default), active-low
36 P2_4 I

I/O pin, default pull-high input

System Configuration,

L: Boot Mode with P2_0 low combination
37 GND P Ground pin
38 NC — No Connection
39 NC — No Connection
40 NC — No Connection
  • I: Input pin
  • O: Output pin
  • I/O: Input/Output pin
  • P: Power pin
Note: All I/O pins can be configured using the IS20XXS_UI tool.

The following figure illustrates the pin diagram of the BM23 module.

Figure 1-4. BM23 Module Pin Diagram
Table 1-2. BM23 Pin Description
Pin No. Name Pin Type Description
1 P0_0 I/O
  • I/O pin, default pull-high input (Note 1)
  • UART TX_IND
2 RFS0 I/O I2S interface: DAC Left/Right clock
3 TFS0 I/O I2S interface: ADC Left/Right clock
4 SLK0 I/O I2S interface: Bit clock
5 DR0 I I2S interface: DAC Digital Left/Right data
6 DT0 O I2S interface: ADC Digital Left/Right data
7 P0_4 I/O I/O pin, default pull-high input
8 EAN I

Embedded ROM/External Flash enable

High: ROM mode;

Low: External Flash mode
9 MIC1_P I MIC 1 mono differential analog positive input
10 MIC1_N I MIC 1 mono differential analog negative input
11 MIC_BIAS P Power output, microphone biasing voltage
12 VDDA P Power output, reserve for external capacitance to fine tune audio frequency
13 AIR I Right-channel, stereo analog line-in
14 AIL I Left-channel, stereo analog line-in
15 GND P Ground
16 RST I System Reset pin, active when rising edge
17 NC — —
18 NC — —
19 VDDIO P Power output, VDDIO pin, no need to add power to this pin
20 P1_5 I/O I/O pin, default pull-high input
21 P0_1 I/O I/O pin, default pull-high input
22 ADAP_IN P 5V power adapter input
23 BAT_IN P 3.3V to 4.2V Li-Ion battery input
24 NC — —
25 SYS_PWR P

System Power Output

BAT mode: 3.3 to 4.2V

Adapter mode: 4.0V
26 BK_OUT P 1.8V power output, no need to add power to this pin
27 MFB P
  • Power key, when in Off mode
  • UART_RX_IND: MCU used to wake up Bluetooth®
28 LED1 P LED driver 1 and maximum 4 mA
29 LED2 P LED driver 2 and maximum 4 mA
30 P2_4 I

I/O pin, default pull-high input

System Configuration,

L– Boot Mode with P2_0 low combination
31 P0_2 I/O I/O pin, default pull-high input
32 P0_3 I/O I/O pin, default pull-high input
33 HCI_TXD O HCI-UART data output
34 HCI_RXD I HCI-UART data input
35 P0_5 I/O I/O pin, default pull-high input
36 P2_7 I/O I/O pin, default pull-high input
37 P2_0 I/O I/O pin, default pull-high input
38 P3_0 I/O I/O pin, default pull-high input
39 P2_0 I

I/O pin, default pull-high input

System Configuration,

H: Application L: Base band (Test Mode)
40 GND P Ground
41 NC — —
42 NC — —
43 NC — —
  • I: Input pin
  • O: Output pin
  • I/O: Input/Output pin
  • P: Power pin
Note: All I/O pins can be configured using the IS20XXS_UI tool.