UM1900 User manual Getting started with the digital MEMS microphones expansion board based on MP34DT01-M for STM32 Nucleo Introduction The X-NUCLEO-CCA02M1 is an evaluation board based on digital MEMS microphones. It is compatible with the Morpho connector layout and is designed around STMicroelectronics MP34DT01-M digital microphones. It has two microphones soldered on board and it is compatible with digital microphone coupon boards such as STEVAL-MKI129Vx and STEVAL-MKI155Vx.
Contents UM1900 Contents 1 Getting started ................................................................................ 3 1.1 2 3 Hardware requirements .................................................................... 3 System requirements ..................................................................... 4 Hardware description ..................................................................... 5 3.1 USB connector and power source .................................................... 5 3.
UM1900 1 Getting started Getting started This section describes the hardware requirements for the X-NUCLEO-CCA02M1 evaluation board. 1.1 Hardware requirements The X-NUCLEO-CCA02M1 is an expansion board for use with STM32 Nucleo boards (please refer to UM1724 on www.st.com for further information). The STM32 Nucleo board must be connected to the X-NUCLEO-CCA02M1 board, as shown in Figure 2: "X-NUCLEO-CCA02M1 on top of STM32 Nucleo board".
System requirements 2 UM1900 System requirements Using the Nucleo boards with the X-NUCLEO-CCA02M1 expansion board requires the following software and hardware: a Windows® (XP, Vista, 7, 8) PC for the software a USB type A to Mini-B USB cable to connect the Nucleo to the PC for installation of the board firmware package (order code: X-CUBE-MEMSMIC1); a utility running on the user's PC will complete the demo.
UM1900 3 Hardware description Hardware description The board allows the user to test the function of the STMicroelectronics MEMS microphones. For this purpose two MP34DT01-M digital MEMS microphone are mounted on the board and 6 headers (4 mounted with 2 additional footprints) are available for connecting additional microphones using digital microphone coupon boards (STEVALMKI129Vx or STEVAL-MKI155Vx), for further information refer to www.st.com.
Hardware description UM1900 In this scenario, microphone acquisition functions thus: a precise clock signal is generated by I²S peripheral while SPI is configured in slave mode and is fed by the same timing signal generated by I²S. This clock is then halved by a timer and input to the microphones: the SPI and I²S peripherals operate at twice the microphone frequency, so that they can read data on both the rising and falling edge of the microphone clock, thus reading the bits of two microphones each.
UM1900 3.3.
Hardware description UM1900 2-microphone acquisition As previously mentioned, this is the case in which the I²S peripheral is used to generate twice the frequency needed by the microphones. In this scenario, the clock is then halved by the timer and routed to the microphones to give them the right clock. I²S therefore reads values from both edges of the merged PDM lines.
UM1900 Hardware description SB Status SB15 Close SB16 Open SB17 Open SB18 Open SB19 Open SB20 Open SB21 Open In addition, J2 and J3 must be placed in position 2-3 for external microphone acquisition.
Connectors 4 UM1900 Connectors The pin assignments for the Arduino UNO R3 and the Morpho connectors are shown in Table 6: "Arduino connector table" and Table 5: "Morpho connector table" respectively.
UM1900 5 Board schematics Board schematics Figure 5: Board schematic (Part 1) Figure 6: Board schematic (Part 2) DocID027905 Rev 1 11/15
Board schematics UM1900 Figure 7: Board schematic (Part 3) Figure 8: Board schematic (Part 4) 12/15 DocID027905 Rev 1
UM1900 6 Layout Layout Figure 9: Top layout Figure 10: Bottom layout DocID027905 Rev 1 13/15
Revision history 7 UM1900 Revision history Table 7: Document revision history 14/15 Date Revision 28-May-2015 1 Changes Initial release.
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