ST STM32H723, Getting Started, Page: 41 / 50

Figure 25. Stereo microphone interconnection
Digital PDM Stereo
Microphones STM32H7
CKOUT
DATIN0
Transceiver 1
Transceiver 0
Transceiver 3
Transceiver 2
Transceiver 5
Transceiver 4
Transceiver 7
Transceiver 6
Filter 1
Filter 0
Filter 3
Filter 2
Filter 5
Filter 4
Filter 7
Filter 6
Channel
Mux
DFSDM1
DATIN1
DA
TA_OUT
CK
DATIN6
DATIN7
This example can be transposed to other kinds of external sensors.
9.4.5 Embedded trace macrocell (ETM)
Interface connectivity
The ETM enables the reconstruction of the program execution. The data is traced using the data watchpoint and
trace (DWT) component or the instruction trace macrocell (ITM) whereas instructions are traced using the
embedded trace macrocell (ETM). The ETM interface is synchronous with the four data bus lines D[0:3] and the
clock signal CLK.
Interface signals layout guidelines
• Reference the plane using GND or PWR (if PWR, add 10 nf stitching capacitor between PWR and GND
• Trace impedance: 50 Ω ± 10%
• All the data trace should be as short as possible (≤25 mm),
• Trace the lines which should run on the same layer with a solid ground plane underneath it without vias.
• Trace the clock which should have only point-to-point connection. Any stubs should be avoided.
• It is strongly recommended also for other (data) lines to be point-to-point only. If any stubs are needed, they
should be as short as possible. If long stubs are required, there should be a possibility to optionally
disconnect them (e.g. by jumpers).
AN5419
High speed signal layout
AN5419 - Rev 2
page 41/50