From d69df42de43c880bf87e4fbabffb7c07969f2172 Mon Sep 17 00:00:00 2001 From: Jonathan Naylor Date: Thu, 11 Jan 2018 18:29:58 +0000 Subject: [PATCH] Add the NXDN TX preamble. --- NXDNTX.cpp | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/NXDNTX.cpp b/NXDNTX.cpp index 2e2ca0a..b3fb55c 100644 --- a/NXDNTX.cpp +++ b/NXDNTX.cpp @@ -34,8 +34,8 @@ const q15_t NXDN_LEVELB = 561; const q15_t NXDN_LEVELC = -561; const q15_t NXDN_LEVELD = -1683; -const uint8_t NXDN_START_SYNC = 0x77U; -const uint8_t NXDN_END_SYNC = 0xFFU; +const uint8_t NXDN_PREAMBLE[] = {0x57U, 0x75U, 0xFDU}; +const uint8_t NXDN_SYNC = 0x5FU; CNXDNTX::CNXDNTX() : m_buffer(1500U), @@ -62,7 +62,10 @@ void CNXDNTX::process() if (m_poLen == 0U) { if (!m_tx) { for (uint16_t i = 0U; i < m_txDelay; i++) - m_poBuffer[m_poLen++] = NXDN_START_SYNC; + m_poBuffer[m_poLen++] = NXDN_SYNC; + m_poBuffer[m_poLen++] = NXDN_PREAMBLE[0U]; + m_poBuffer[m_poLen++] = NXDN_PREAMBLE[1U]; + m_poBuffer[m_poLen++] = NXDN_PREAMBLE[2U]; } else { for (uint8_t i = 0U; i < NXDN_FRAME_LENGTH_BYTES; i++) { uint8_t c = m_buffer.get();