designguard 0.1.1

KiCad schematic and PCB validation library
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103

{
  "part_numbers": ["ATmega328P", "ATmega328P-PU", "ATmega328P-AU", "ATMEGA328P", "ATmega328"],
  "manufacturer": "Microchip/Atmel",
  "category": "microcontroller",
  "power_requirements": [
    {
      "pin_name": "VCC",
      "voltage_min": 1.8,
      "voltage_max": 5.5,
      "voltage_typical": 5.0,
      "current_max": 0.2
    },
    {
      "pin_name": "AVCC",
      "voltage_min": 1.8,
      "voltage_max": 5.5,
      "voltage_typical": 5.0,
      "current_max": 0.01
    }
  ],
  "decoupling_requirements": [
    {
      "power_pin": "VCC",
      "capacitance": { "min": 100e-9, "typical": 100e-9, "max": null },
      "max_distance_mm": 10.0,
      "capacitor_type": "ceramic",
      "esr_requirement": null,
      "capacitor_role": "bypass",
      "severity": "warning",
      "reason": "100nF ceramic capacitor on VCC for digital supply decoupling."
    },
    {
      "power_pin": "AVCC",
      "capacitance": { "min": 100e-9, "typical": 100e-9, "max": null },
      "max_distance_mm": 10.0,
      "capacitor_type": "ceramic",
      "esr_requirement": null,
      "capacitor_role": "bypass",
      "severity": "warning",
      "reason": "100nF on AVCC required even if ADC not used. AVCC powers port drivers."
    }
  ],
  "external_components": [
    {
      "component_type": {
        "type": "crystal",
        "frequency_hz": 16000000.0,
        "load_capacitance_pf": 22.0
      },
      "connected_pins": ["XTAL1", "XTAL2"],
      "value_requirement": { "min": null, "typical": 16000000.0, "max": 20000000.0, "unit": "Hz" },
      "required": false,
      "reason": "External crystal optional - internal 8MHz RC oscillator available. For precise timing, use 16MHz crystal with 22pF load caps."
    },
    {
      "component_type": { "type": "pull_up_resistor" },
      "connected_pins": ["RESET"],
      "value_requirement": { "min": 10000.0, "typical": 10000.0, "max": null, "unit": "Ω" },
      "required": true,
      "reason": "10k pull-up on RESET prevents spurious resets from noise. Internal pull-up is weak (~50k)."
    },
    {
      "component_type": { "type": "reset_capacitor" },
      "connected_pins": ["RESET"],
      "value_requirement": { "min": 100e-9, "typical": 100e-9, "max": null, "unit": "F" },
      "required": false,
      "reason": "Optional 100nF cap on RESET for noise filtering. Required if long reset traces."
    },
    {
      "component_type": { "type": "filter_capacitor" },
      "connected_pins": ["AREF"],
      "value_requirement": { "min": 100e-9, "typical": 100e-9, "max": null, "unit": "F" },
      "required": false,
      "reason": "100nF on AREF if using ADC with external reference. Filters reference noise."
    }
  ],
  "pin_requirements": [
    {
      "pin_name": "RESET",
      "requirement": {
        "type": "pull_up",
        "resistance_ohms": { "min": 10000.0, "typical": 10000.0, "max": null, "unit": "Ω" }
      },
      "reason": "RESET needs external 10k pull-up for noise immunity. Internal pull-up alone is insufficient in noisy environments."
    }
  ],
  "absolute_max_ratings": {
    "vcc_max": 6.0,
    "io_voltage_max": 5.5,
    "io_current_max": 0.040,
    "storage_temp_min": -65.0,
    "storage_temp_max": 150.0,
    "operating_temp_min": -40.0,
    "operating_temp_max": 85.0,
    "esd_hbm": null
  },
  "warnings": [
    "AVCC must be connected even if ADC is not used",
    "Connect unused analog inputs to GND to reduce noise",
    "Total current through VCC/GND must not exceed 200mA"
  ],
  "datasheet_url": "https://ww1.microchip.com/downloads/en/DeviceDoc/ATmega328P-Complete-Datasheet-40001984A.pdf"
}