Introduction of the connecting circuit between ad7606 and stm32

   AD7606/AD7606-6/AD7606-4 by Analog Device company-made 16 Bit synchronous sampling analog-to-digital data acquisition system （DAS）, There were 8、6、4 Two acquisition channels .

• Input Clamp Protection , To withstand up to ±16.5V The voltage of
• 40 dB Second order anti aliasing filter
• Track and hold amplifier
• 16 Potential charge redistribution successive approximation type ADC kernel
• Digital filter
• 2.5V Reference voltage source and buffer
• High speed serial and parallel interfaces
• 5V Single power supply
• Support real ±10V or ±5V Bipolar signal input
• All channels can reach 200 kSPS Sample at a rate of
• Built in low noise 、 Signal conditioning circuit with high input impedance , Its equivalent input impedance is completely independent of the sampling rate and is fixed to 1MΩ
• built-in 2.5V Bandgap voltage reference and reference buffer circuit , The typical value of its temperature coefficient is ±10ppm/℃, The use of internal and external datums is optional
• Oversampling and digital filtering functions

 

AD7606 Schematic diagram

AD7606 Total needs 9 A decoupling capacitor can ensure its stable operation , Include 4 Power pins AVcc（100nf）、REFCAPA（REFCAPB） Pins and REFIN/REFOUT Pin （10μF Polar capacitance ）、 Two REGCAP Pin （1μF） And logic power supply pin Vdrive（100nf）.

 

AD7606 And STM32 The schematic diagram of circuit connection between is shown in the figure ：

　　（1）AD7606 Three interface options are provided ： Parallel interface 、 High speed serial interface and parallel byte interface . The parallel interface has the highest data transmission speed , And with STM32 Of FSMC（FlexibleStaticMemoryController, Variable static storage controller ） compatible . So two pieces AD7606 And STM32 Connect through parallel interface .AD7606 The data line DB0~DB15 Connect the corresponding... Respectively FSMC cable , The chip selection signals are respectively received FSMC Interface chip selection signal PG9_FSMC_NE2 and PG12_FSMC_NE4 On .

　　（2）AD7606 Of BUSY When the pin level is high, it means AD Conversion in progress , Lowering indicates that the conversion is complete . take BUSY Pin to STM32 The external interrupt pin is configured to trigger on the falling edge , This can be done in AF Read the data in time after the conversion .

　　（3）OS［0..2］ Configure pins for oversampling , By controlling STM32 relevant GPIO The level of can be AD7606 Working in different oversampling States .

　　（4）CONVST_A,CONVST_B For switching trigger signal , Rising edge trigger . For each of these AD7606 Come on ,CONVST_A Control analog channel 1~4,CONVST_B Control analog channel 5~8. Because all channels need to be sampled synchronously , So it will CONVST_A,CONVST_B The pin is simultaneously connected to a trigger signal pin to realize synchronous sampling .

　　（5）REFOUT The pin is the external reference voltage input pin .AD7606 It can be configured to use internal reference voltage or external reference voltage . When two pieces AD7606 At the same time , Using external reference voltage can ensure the consistency of conversion accuracy of all input channels . External reference voltage source selection ADR421,ADR421 by 2.5V Reference power , Excellent noise performance 、 Stability and accuracy , You can meet AD Accuracy requirements for reference voltage source .