(kicad_sch (version 20211014) (generator kiutils)
  (paper "A5")
  (title_block
    (title "One verified 74HC595 output stage · 8 independent channels")
    (date "2026-08-27")
    (rev "B · electrically re-audited")
    (company "Kangwon National University Psychology Lab")
    (comment 1 "Reconstructed from source code, build photographs, and SN74HC595 datasheet")
    (comment 2 "No undocumented IDC pin-to-channel mapping has been invented")
  )
  (lib_symbols
    (symbol "Device:R_Small" (pin_numbers hide) (pin_names (offset 0.254) hide) (in_bom yes) (on_board yes)
      (property "Reference" "R" (at 0.762 0.508 0))
      (property "Value" "R_Small" (at 0.762 -1.016 0))
      (property "Footprint" "" (at 0 0 0))
      (property "Datasheet" "~" (at 0 0 0))
      (property "ki_keywords" "R resistor" (at 0 0 0))
      (property "ki_description" "Resistor, small symbol" (at 0 0 0))
      (property "ki_fp_filters" "R_*" (at 0 0 0))
      (symbol "R_Small_0_1"
        (rectangle (start -0.762 1.778) (end 0.762 -1.778)
          (fill (type none))
        )
      )
      (symbol "R_Small_1_1"
        (pin passive line (at 0 2.54 270) (length 0.762)
          (name "~")
          (number "1")
        )
        (pin passive line (at 0 -2.54 90) (length 0.762)
          (name "~")
          (number "2")
        )
      )
    )
    (symbol "74xx:74HC595" (in_bom yes) (on_board yes)
      (property "Reference" "U" (at -7.62 13.97 0))
      (property "Value" "74HC595" (at -7.62 -16.51 0))
      (property "Footprint" "" (at 0 0 0))
      (property "Datasheet" "http://www.ti.com/lit/ds/symlink/sn74hc595.pdf" (at 0 0 0))
      (property "ki_keywords" "HCMOS SR 3State" (at 0 0 0))
      (property "ki_description" "8-bit serial in/out Shift Register 3-State Outputs" (at 0 0 0))
      (property "ki_fp_filters" "DIP*W7.62mm* SOIC*3.9x9.9mm*P1.27mm* TSSOP*4.4x5mm*P0.65mm* SOIC*5.3x10.2mm*P1.27mm* SOIC*7.5x10.3mm*P1.27mm*" (at 0 0 0))
      (symbol "74HC595_1_0"
        (pin tri_state line (at 10.16 7.62 180) (length 2.54)
          (name "QB")
          (number "1")
        )
        (pin input line (at -10.16 2.54 0) (length 2.54)
          (name "~{SRCLR}")
          (number "10")
        )
        (pin input line (at -10.16 5.08 0) (length 2.54)
          (name "SRCLK")
          (number "11")
        )
        (pin input line (at -10.16 -2.54 0) (length 2.54)
          (name "RCLK")
          (number "12")
        )
        (pin input line (at -10.16 -5.08 0) (length 2.54)
          (name "~{OE}")
          (number "13")
        )
        (pin input line (at -10.16 10.16 0) (length 2.54)
          (name "SER")
          (number "14")
        )
        (pin tri_state line (at 10.16 10.16 180) (length 2.54)
          (name "QA")
          (number "15")
        )
        (pin power_in line (at 0 15.24 270) (length 2.54)
          (name "VCC")
          (number "16")
        )
        (pin tri_state line (at 10.16 5.08 180) (length 2.54)
          (name "QC")
          (number "2")
        )
        (pin tri_state line (at 10.16 2.54 180) (length 2.54)
          (name "QD")
          (number "3")
        )
        (pin tri_state line (at 10.16 0 180) (length 2.54)
          (name "QE")
          (number "4")
        )
        (pin tri_state line (at 10.16 -2.54 180) (length 2.54)
          (name "QF")
          (number "5")
        )
        (pin tri_state line (at 10.16 -5.08 180) (length 2.54)
          (name "QG")
          (number "6")
        )
        (pin tri_state line (at 10.16 -7.62 180) (length 2.54)
          (name "QH")
          (number "7")
        )
        (pin power_in line (at 0 -17.78 90) (length 2.54)
          (name "GND")
          (number "8")
        )
        (pin output line (at 10.16 -12.7 180) (length 2.54)
          (name "QH'")
          (number "9")
        )
      )
      (symbol "74HC595_1_1"
        (rectangle (start -7.62 12.7) (end 7.62 -15.24)
          (fill (type background))
        )
      )
    )
  )
  (wire (pts (xy 44.84 61.84) (xy 36.0 61.84)))
  (wire (pts (xy 44.84 66.92) (xy 36.0 66.92)))
  (wire (pts (xy 44.84 69.46) (xy 36.0 69.46)))
  (wire (pts (xy 44.84 74.54) (xy 36.0 74.54)))
  (wire (pts (xy 44.84 77.08) (xy 36.0 77.08)))
  (wire (pts (xy 55.0 56.76) (xy 55.0 50.0)))
  (wire (pts (xy 55.0 89.78) (xy 55.0 96.0)))
  (wire (pts (xy 65.16 84.7) (xy 75.0 84.7)))
  (wire (pts (xy 65.16 61.84) (xy 77.0 61.84)))
  (wire (pts (xy 122.46 43.0) (xy 112.0 43.0)))
  (wire (pts (xy 127.54 43.0) (xy 138.0 43.0)))
  (wire (pts (xy 65.16 64.38) (xy 77.0 64.38)))
  (wire (pts (xy 122.46 52.0) (xy 112.0 52.0)))
  (wire (pts (xy 127.54 52.0) (xy 138.0 52.0)))
  (wire (pts (xy 65.16 66.92) (xy 77.0 66.92)))
  (wire (pts (xy 122.46 61.0) (xy 112.0 61.0)))
  (wire (pts (xy 127.54 61.0) (xy 138.0 61.0)))
  (wire (pts (xy 65.16 69.46) (xy 77.0 69.46)))
  (wire (pts (xy 122.46 70.0) (xy 112.0 70.0)))
  (wire (pts (xy 127.54 70.0) (xy 138.0 70.0)))
  (wire (pts (xy 65.16 72.0) (xy 77.0 72.0)))
  (wire (pts (xy 122.46 79.0) (xy 112.0 79.0)))
  (wire (pts (xy 127.54 79.0) (xy 138.0 79.0)))
  (wire (pts (xy 65.16 74.54) (xy 77.0 74.54)))
  (wire (pts (xy 122.46 88.0) (xy 112.0 88.0)))
  (wire (pts (xy 127.54 88.0) (xy 138.0 88.0)))
  (wire (pts (xy 65.16 77.08) (xy 77.0 77.08)))
  (wire (pts (xy 122.46 97.0) (xy 112.0 97.0)))
  (wire (pts (xy 127.54 97.0) (xy 138.0 97.0)))
  (wire (pts (xy 65.16 79.62) (xy 77.0 79.62)))
  (wire (pts (xy 122.46 106.0) (xy 112.0 106.0)))
  (wire (pts (xy 127.54 106.0) (xy 138.0 106.0)))
  (text "SHEET E-01 · ONE 8-CHANNEL OUTPUT STAGE" (at 18 17 0))
  (text "Every QA…QH output has its own net and its own 150 ohm series resistor."
    (at 18 26 0)
  )
  (text "Repeated 7 times per side board; 14 stages total for 112 outputs."
    (at 18 32 0)
  )
  (text "Pin 10 SRCLR = +5 V; pin 13 OE = GND." (at 18 116 0))
  (text "As built: 150 ohm, 1/4 W, 5%. Re-check LED and package current limits before redesign."
    (at 18 122 0)
  )
  (text "3.3 V GPIO drives a 5 V 74HC595; review the logic-high margin for a new revision."
    (at 18 128 0)
  )
  (text "QA · pin 15" (at 87.0 43.7 0))
  (text "QB · pin 1" (at 87.0 52.7 0))
  (text "QC · pin 2" (at 87.0 61.7 0))
  (text "QD · pin 3" (at 87.0 70.7 0))
  (text "QE · pin 4" (at 87.0 79.7 0))
  (text "QF · pin 5" (at 87.0 88.7 0))
  (text "QG · pin 6" (at 87.0 97.7 0))
  (text "QH · pin 7" (at 87.0 106.7 0))
  (label "SER_IN" (at 36.0 61.84 180))
  (label "SRCLK_BCM17" (at 36.0 66.92 180))
  (label "+5V_SRCLR" (at 36.0 69.46 180))
  (label "RCLK_BCM27" (at 36.0 74.54 180))
  (label "GND_OE" (at 36.0 77.08 180))
  (label "+5V" (at 55.0 50.0 90))
  (label "GND" (at 55.0 96.0 90))
  (label "QHPRIME_TO_NEXT_SER" (at 75.0 84.7 0))
  (label "U1_QA_RAW" (at 77.0 61.84 0))
  (label "U1_QA_RAW" (at 112.0 43.0 180))
  (label "CH0" (at 138.0 43.0 0))
  (label "U1_QB_RAW" (at 77.0 64.38 0))
  (label "U1_QB_RAW" (at 112.0 52.0 180))
  (label "CH1" (at 138.0 52.0 0))
  (label "U1_QC_RAW" (at 77.0 66.92 0))
  (label "U1_QC_RAW" (at 112.0 61.0 180))
  (label "CH2" (at 138.0 61.0 0))
  (label "U1_QD_RAW" (at 77.0 69.46 0))
  (label "U1_QD_RAW" (at 112.0 70.0 180))
  (label "CH3" (at 138.0 70.0 0))
  (label "U1_QE_RAW" (at 77.0 72.0 0))
  (label "U1_QE_RAW" (at 112.0 79.0 180))
  (label "CH4" (at 138.0 79.0 0))
  (label "U1_QF_RAW" (at 77.0 74.54 0))
  (label "U1_QF_RAW" (at 112.0 88.0 180))
  (label "CH5" (at 138.0 88.0 0))
  (label "U1_QG_RAW" (at 77.0 77.08 0))
  (label "U1_QG_RAW" (at 112.0 97.0 180))
  (label "CH6" (at 138.0 97.0 0))
  (label "U1_QH_RAW" (at 77.0 79.62 0))
  (label "U1_QH_RAW" (at 112.0 106.0 180))
  (label "CH7" (at 138.0 106.0 0))
  (symbol (lib_id "74xx:74HC595") (at 55.0 72.0 0) (unit 1)
    (in_bom yes) (on_board yes) (dnp no)
    (property "Reference" "U1" (at 51.0 52.0 0))
    (property "Value" "74HC595" (at 49.5 92.0 0))
    (property "Footprint" "Package_DIP:DIP-16_W7.62mm" (at 55.0 72.0 0))
    (property "Datasheet" "https://www.ti.com/lit/ds/symlink/sn74hc595.pdf" (at 55.0 72.0 0))
    (pin "1")
    (pin "2")
    (pin "3")
    (pin "4")
    (pin "5")
    (pin "6")
    (pin "7")
    (pin "8")
    (pin "9")
    (pin "10")
    (pin "11")
    (pin "12")
    (pin "13")
    (pin "14")
    (pin "15")
    (pin "16")
    (instances
      (project "psychology-lab-led-controller-verified"
        (path
          (reference "U1") (unit 1)
        )
      )
    )
  )
  (symbol (lib_id "Device:R_Small") (at 125.0 43.0 90) (unit 1)
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    (property "Reference" "R1" (at 118.0 41.0 0))
    (property "Value" "150R" (at 124.5 41.0 0))
    (property "Footprint" "Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal" (at 125.0 43.0 0))
    (property "Datasheet" "~" (at 125.0 43.0 0))
    (pin "1")
    (pin "2")
    (instances
      (project "psychology-lab-led-controller-verified"
        (path
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  )
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    (property "Reference" "R2" (at 118.0 50.0 0))
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    (property "Footprint" "Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal" (at 125.0 52.0 0))
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  )
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)
