Product Info

LTE Standard Module Series
EC21 Hardware Design
EC21_Hardware_Design 61 / 120
PCM_IN
1)
24 DI PCM data input 1.8V power domain
PCM_OUT
1)
25 DO PCM data output 1.8V power domain
PCM_SYNC
1)
26 IO
PCM data frame synchronization
signal
1.8V power domain
PCM_CLK
1)
27 IO PCM data bit clock 1.8V power domain
BT_EN 139 DO
BT function control via FC20
module.
1.8V power domain
Active high.
The following figure shows a reference design of wireless connectivity interfaces with Quectel FC20
module.
Module
WAKE_ON_WIRELESS
WLAN_SLP _CLK
PM_ENABL E
DCDC/LDO
32KHZ_IN
WAKE_ON_WIRELESS
FC20 Module
VDD_3V3
POWER
SDC1_DATA3
SDC1_DATA2
SDC1_DATA1
SDC1_DATA0
SDC1_CLK
SDC1_CMD
WLAN_EN
SDIO_D3
SDIO_D2
SDIO_D1
SDIO_D0
SDIO_CLK
SDIO_CMD
WLAN_EN
WLAN
BT_EN
BT_RTS
BT_CTS
BT_TXD
BT_RXD
PCM_IN
PCM_OUT
PCM_SYNC
PCM_CLK
BT_EN
BT_UART_RTS
BT_UART_CTS
BT_UART_RXD
BT_UART_TXD
PCM_OUT
PCM_IN
PCM_SYNC
PCM_CLK
VDD_EXT VIO
COEX_UART_TX
COEX_UART_RX
LTE_UART_TXD
LTE_UART_RXD
COEX
Bluetooth*
Figure 26: Reference Circuit of Wireless Connectivity Interfaces with FC20 Module
1. FC20 module can only be used as a slave device.
2. When BT function is enabled on EC21 module, PCM_SYNC and PCM_CLK pins are only used to
output signals. BT function is under development.
3.
1)
Pads 24~27 are multiplexing pins used for audio design on EC21 module and BT function on BT
NOTES