PRIMARY AUTHORITY PATH
Absurdly Accurate Clock
Pico 2 / RP2350
Sole external authoritative source
AAC Protocol v1 source
ACT1 · 40-byte immutable snapshot
Qualified UTC/PPS boundary
UTC + PPS identity + TIME_SYNC association
SPI clocks · dummy MOSI
ESP32 controller → Pico
40-byte ACT1 snapshot
Pico → ESP32 over MISO
TIME_SYNC rising edge
software-delayed
boundary association
AAC Time Bridge
ESP32 / NodeMCU-32S
Network appliance · read-only consumer of AAC authority
1 · Protocol acquisition
SPI mode 1 · 100 kHz
magic/version/length/CRC
flags + sequences + epoch
2 · Edge association
capture TIME_SYNC edge
apply sync_delay_us relationship
pair edge ↔ snapshot boundary
3 · Qualification / authority state
UTC_VALID · PPS_PRESENT · PPS_LOCKED · SYNC_VALID
clean edge relationship · sequence continuity
freshness deadline: 1.5 s
Responding is not the same as qualified.
Central appliance state
qualified UTC anchor
source / network / reset
watchdog / build / uptime
LAN NTP service
UDP/123 · NTP v3/v4
qualified: Stratum 1
Reference ID: “AAC ”
qualified UTC
Infrastructure LAN
Normal station Wi-Fi / LAN address
NTP clients
workstations · servers · devices
basic NTP v3/v4 requests
NTP · UDP/123
derived from qualified AAC clock state
Local WebUI / browser
Presentation + management client
GET /telemetry ≈ 1×/s
latest bounded snapshot only
Browser never becomes a clock authority.
Fail-safe: UNSYNCHRONIZED
Authority is withdrawn on invalid, unqualified, stale,
or discontinuous source state.
LI = 3
Stratum 16
Reference ID “INIT”
reference / receive / transmit timestamps = 0
Wi-Fi, WebUI, watchdog and appliance execution continue.
No Internet NTP, ESP32 wall clock, browser clock,
stale-time or synthetic-authority fallback exists.
qualification lost
Recovery / provisioning
AAC-Bridge-XXXXXX
192.168.4.1
Configuration and recovery only.
NTP is not exposed on the setup AP.
SECONDARY APPLIANCE FUNCTIONS
30 s application watchdog
Recovery not yet hardware bench-validated
GPIO16 status LED
Consumes centralized appliance state
IMPLEMENTATION / VALIDATION
SPI/TIME_SYNC acquisition: implemented + bench-confirmed
Qualified AAC UTC + sequence/phase association: confirmed
Absolute UTC error: not yet physically qualified
authoritative timing/data
LAN NTP
WebUI/status
recovery/config