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https://github.com/portapack-mayhem/mayhem-firmware.git
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Sarah Rose
5c2d1d3dfb
Implements MDC-1200 single and double-packet TX as a PPMA external app. Features: - Supports PTT ID, Emergency, Radio Check, Stun/Unstun, Call Alert, Selective Call (1 & 2), Status Request/Response, Remote Monitor, Message - Auto-fills Arg byte on Op selection - AFSK FSK modulation: 1800 Hz mark / 1200 Hz space, 1200 baud - NRZI encoding with Golay FEC per MDC-1200 spec - Tap-to-edit frequency via keypad - Default TX gain of 30 dB - Uses AFSK baseband (same as POCSAG/SAME TX) - All buffers kept off the stack to avoid hard faults in ext app environment * mdc_tx: address PR review feedback - Move MDC helpers into ui::external_app::mdc_tx namespace (drop anonymous namespace) - Use AFSK_TX_SAMPLERATE macro instead of hardcoded 1536000 - Add #include "modems.hpp" explicitly for AFSK_TX_SAMPLERATE - Replace n*8/n*16 pixel positions with UI_POS_X/UI_POS_Y macros - Fix field comments: 'hex bytes' -> 'decimal bytes (0-255)' - Fix TransmitterView frequency_step: 1750000 -> 12500 (12.5kHz NFM step) - Fix MDC preamble: replace leading 0x00 bytes with 0xAA after NRZI encoding stayed 0x00, terminating TX on the first word. 0xAA bytes NRZI-encode to 0xFF (continuous 1800Hz mark tone), which is the standard MDC-1200 preamble and does not trigger the sentinel.