3.5 PDM Stereo Microphones
The Thunderboard EFM32GG12 features two Knowles SPK0641HT4H-1 digital MEMS microphones with PDM output. The micro-
phones are configured to form a stereo sound input device using only a single PDM data line. The clock to the microphones are fed
from a pin on EFM32GG12 with PDM clock support. The output from both microphones are connected to the same line and connected
to a pin on the EFM32GG12 supporting PDM data input. An isolation switch controlled by the microphone enable signal powers the
microphones on and off. Note that the switch allows for free use of the PDM data and clock GPIOs when not in use with the micro-
phones.
PB11 (PDM_DAT0 #3)
PB12 (PDM_CLK #3)
EFM32
PDM MEMS
Microphone (R)
PDM MEMS
Microphone (L)
VDD
PDM_CLK
PDM_CLK
PDM_DATA
PDM_DATA
VDD
MIC_ENABLE
PA8 (GPIO)
MIC_DATA
MIC_CLOCK
VMCU
Figure 3.6. Digital Stereo Microphones
3.6 On-board Debugger
The Thunderboard EFM32GG12 contains a microcontroller separate from the EFM32GG12 Giant Gecko that provides the user with a
on-board J-Link debugger through the USB micro-B debugging port. This microcontroller is referred to as the "On-board Debugger",
and is not programmable by the user.
In addition to providing code download and debug features, the on-board debugger also presents a virtual COM port for general pur-
pose application serial data transfer.
Figure 3.7 On-Board Debugger Connections on page 8
shows the connections between the target EFM32GG12 device and the on-
board debugger. The figure also shows the presence of the Mini Simplicity Connector, and how this is connected to the same I/O pins.
Please refer to section
4. Debugging
and section
5. Kit Configuration and Upgrades
for more details on debugging.
EFR32MG
VCOM_TX
VCOM_RX
VCOM_CTS
VCOM_RTS
DBG_SWCLK
DBG_SWDIO
DBG_SWO
On-Board
J-Link
Debugger
Host
PC
USB
DBG_RESET
Mini Simplicity
Connector
PC11 (I2C0_SCL#15)
PF0 (DBG_SCLK)
PF1 (DBG_SWDIO)
PF2 (DBG_SWO#0)
PE7 (US0_TX#1)
PE6 (US0_RX#1)
PB5 (US0_RTS#4)
PB6 (US0_CTS#4)
RESETn
EFM32
Isolation & Levelshift
Figure 3.7. On-Board Debugger Connections
UG371: Thunderboard EFM32GG12 User's Guide
Hardware
silabs.com
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