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#Specification VMAC-2

VMAC v2 specification overview:

  • Full size quality two layer Raspberry Pi Hat board to HAT mechanical specification
    • Suitable for Raspberry PI 2, 3 or ZeroĀ Ā ModelsĀ  Raspberry Family
  • Size 85mm x 56mm
  • Weight: PCB with connectors 40g, PCB without connectors 20g
  • Standard 40 pin Pi GPIO header
  • All logic I/O (GPIO), levels are at 3v3
  • Impedance Video 75 Ohms and Audio 600 Ohms (Line Level)
  • Programmable individual Video input Clamp, Bias and Gain
  • 9 x AV Inputs to Matrix
    • 6 x RCA Sockets ā€“ Component configurable for Video or Audio Inputs
    • 3.5mm Jack Socket providing (Used to loopback from Pi 3.5mm Socket)
      • 1 x video Input
      • 2 x audio Inputs
  • 4 x AV Outputs from Matrix
    • 4 x RCA Sockets – Component configurable for Video or Audio Outputs
  • Pi Zero video connector Pin Header
  • 4 x matrix logic control inputs
    • Connected to GPIO on Pi GPIO header
  • FET switched output (Intended for PTT)
    • Connected via GPIO on Pi GPIO header
  • PiHat powered from on-board 3V3 regulator
    • Taking 5V from Pi Header
  • DTMF decoder (CM88L80)
    • Logic outputs to GPIO on Pi GPIO header
    • Level control preset on PCB
  • OSD (MAX7456)
    • Controlled from SPI on Pi GPIO header
  • 3 x Video Signal Detectors (MAX7461)
    • Connected to AV Inputs 1, 2 and 3
    • Logic outputs to GPIO on Pi GPIO header
  • 4 x On-board LEDs.Ā  3v3 Power, User, Status and PTT
  • EEPROM
    • Optionally connected to either E2 ID, or I2C, on Pi GPIO header
  • UART TXD, RXD and RTS
    • Connected to GPIO on Pi GPIO header
    • RTS is also connected to a LED, allowing multiple use
  • Two PiHat boards may be stacked for increased A/V IO count
    • Require to unpopulate DTMF on 2nd board
    • Require to clear EEPROM solder jumper on 2nd board
    • Change matrix I2C address via solder jumperĀ on 2nd board
  • Eleven test points on PCB for expansion, testing or other uses
  • Mounting holes
    • Suitable for Raspberry PI 2, 3 or Zero risers
  • Component Temperature Range 0Ā°C to 85Ā°C
  • Operating TemperatureĀ  Range 0Ā°C to 45Ā°C
    • Air movement over PCB is advisable at high temperatures