Clock Sources; Reset Sources; Audio - ST STM32F746G-DISCO User Manual

UM1907
1. If more than 500 mA current is needed by the board, the PC may be damaged or
current can be limited by the PC. As a consequence the board is not powered correctly.
2. 500 mA will be requested at the enumeration, so there is a risk that the request is
rejected and enumeration does not succeed if the PC cannot provide such current.
6.4

Clock sources

Up to 3 clock sources as described below:
•
X1, 24 MHz oscillator for the USB OTG HS PHY and camera module (daughterboard)
•
X2, 25 MHz oscillator for the STM32F746NGH6 microcontroller and Ethernet PHY
•
X3, 32 KHz crystal for the STM32F746NGH6 embedded RTC
6.5

Reset sources

The reset signal of STM32F746G-DISCO discovery board is active low and the reset
sources include:
•
Reset button B2
•
Arduino Uno shield board from CN6
•
Embedded ST-LINK/V2-1
6.6

Audio

An audio codec WM8994ECS/R from CIRRUS with 4 DACs and 2ADCs is connected to SAI
interface of STM32F746NGH6. It communicates with STM32F746NGH6 via I
with the camera module and I
•
The analog line input is connected to ADC of WM8994ECS/R through blue audio jack
CN11.
•
The analog line output is connected to DAC of WM8994ECS/R via green audio jack
CN10.
•
Two external speakers can be connected to WM8994ECS/R via JP3 for right speaker
and JP4 for left speaker.
•
Two digital microphones (ST MEMs microphone) MP34DT01TR are on the
STM32F746G-DISCO discovery board. They are connected to the input digital
microphones of WM8994ECS/R.
• One coaxial connector CN1 is implemented on STM32F746G-DISCO to receive
external audio data compatible with SPDIF specification.
2
C extension connector.
DocID027942 Rev 3
Hardware layout and configuration
2
C bus shared
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