Dual MCU Design Explanation

why their are two MCU ?
Short answer: we split duties between two MCUs to keep the EEG acquisition deterministic and quiet, while offloading wireless and app features.
  • U3: real-time host for the dual ADS1299s, clocked SPI/DMA capture, precise timing, and local tasks like storage. This keeps jitter low and digital noise away from the sensitive analog front end.
  • U8: handles wireless/connectivity and higher-level tasks so the acquisition MCU doesn’t get interrupted by networking stacks.
Benefits:
  • Deterministic sampling and lower coupling into the analog front end (prioritize ground separation over supply separation to reduce noise return-path coupling).
  • Cleaner isolation boundary: the noisy RF/stack side is kept off the patient-side analog domain.
  • Robustness: connectivity issues don’t stall or jitter the data-acquisition loop.
If you’d prefer a single-MCU approach, we can discuss the trade-offs (more jitter/interrupt load near the AFE, tighter noise controls, and isolation constraints).
Prefer single MCU
Clarify MCU connection
Noise isolation guidance
Sampling requirements
Power/EMI concern
U5 -Vout - C24 P2
U5 -Vout - C24 P2
U5 -Vout - C24 P2
U5 -Vout - C24 P2
U5 +Vin - C24 P1
U6 IN - C26 P1
C26
Capacitance
10 uF
U6 OUT - C27 P1
U5 +Vout - C25 P1
C24
Capacitance
10 uF
C25
Capacitance
10 uF
C27
Capacitance
10 uF
U7


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Battery-isolated 16-channel medical-grade EEG front end using dual ADS1299 analog front-ends and an STM32F405 host with integrated WiFi and microSD (SDIO), featuring corrected isolation, and robust low-jitter clock distribution for dual ADS1299 #WiFi #microSD #Isolation #Clocking #ADS1299 #STM32

Properties

Diagram


""Patient Side"" ""Host Side"" "2x8 Header\n(Pins 1-16)" "Patient Analog Front End" "Isolated Power" "Digital Isolation" "Low-Jitter Oscillator" "Host MCU\n(STM32F405)" "WiFi Module" "microSD Card Slot"

Pricing & Availability

Distributor

Qty 1

Arrow

$100.45–$190.86

Digi-Key

$120.93–$122.68

LCSC

$81.79–$101.52

Mouser

$194.58

TME

$23.96

Verical

$93.28–$200.73

Controls