Reorganize code in prep for hardware decoupling and port to C++

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-08-07 01:13:18 +00:00 · 2026-06-22 18:13:15 -07:00
parent d4e05a6da9
commit fb130559e2
16 changed files with 2134 additions and 1673 deletions
@@ -0,0 +1,92 @@
+/*
+                        AVCLAN-Mockingboard
+    Copyright (C) 2015 Allen Hill <allenofthehills@gmail.com>
+
+    Portions of the following source code are based on code that is
+    copyright (C) 2006 Marcin Slonicki <marcin@softservice.com.pl>
+    copyright (C) 2007 Louis Frigon
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+// AVC-LAN PHY: bus bit-banging via TCB timers + analog comparator AC2.
+// This is the lowest layer and has no dependencies on the higher layers
+// (frame / protocol / cdchanger) — keep it that way.
+
+#ifndef AVCLAN_PHY_H
+#define AVCLAN_PHY_H
+
+#include <avr/io.h>
+#include <avr/sfr_defs.h>
+#include <stdint.h>
+
+#include "avclan_defs.h"
+
+// AVC LAN bus on AC2 (PA6/7)
+// PA6 AINP0 +
+// PA7 AINN1 -
+#define BUS_IS_IDLE (bit_is_clear(AC2_STATUS, AC_STATE_bp))
+
+typedef enum avclan_bit : uint8_t {
+  bit_zero = 0x00,
+  bit_one = 0x01,
+  bit_start = 0x10
+} avclan_bit_t;
+
+// One-time hardware bring-up for the PHY: AC2, EVSYS, TCB0/TCB1, the AC inputs
+// (PA6/7) and AC2-OUT LED (PB2). Leaves the bus idle and TX unmuted.
+void AVCLAN_phyInit();
+
+// Returns true if device TX is muted on AVCLAN bus
+static inline bool AVCLAN_ismuted() {
+  return (((VPORTA_DIR & PIN4_bm) | (VPORTA_DIR & PIN0_bm)) == 0);
+}
+
+// Mute device TX on AVCLAN bus
+void AVCLAN_muteDevice(bool mute);
+
+void AVCLAN_sendbit(avclan_bit_t bit);
+void AVCLAN_sendbit_ACK();
+uint8_t AVCLAN_readbit_ACK();
+
+avclan_bit_t AVCLAN_sendbitsi(const uint8_t *bits, int8_t len);
+avclan_bit_t AVCLAN_sendbitsl(const uint16_t *bits, int8_t len);
+avclan_bit_t AVCLAN_sendbyte(const uint8_t *byte);
+
+uint8_t AVCLAN_readbitsi(uint8_t *bits, uint8_t len);
+uint8_t AVCLAN_readbitsl(uint16_t *bits, int8_t len);
+uint8_t AVCLAN_readbyte(uint8_t *byte);
+
+#define AVCLAN_sendbits(bits, len)                                             \
+  _Generic((bits),                                                             \
+      const uint16_t *: AVCLAN_sendbitsl,                                      \
+      uint16_t *: AVCLAN_sendbitsl,                                            \
+      const uint8_t *: AVCLAN_sendbitsi,                                       \
+      uint8_t *: AVCLAN_sendbitsi)(bits, len)
+
+#define AVCLAN_readbits(bits, len)                                             \
+  _Generic((bits),                                                             \
+      const uint16_t *: AVCLAN_readbitsl,                                      \
+      uint16_t *: AVCLAN_readbitsl,                                            \
+      const uint8_t *: AVCLAN_readbitsi,                                       \
+      uint8_t *: AVCLAN_readbitsi)(bits, len)
+
+#ifndef NDEBUG
+// Bit-timing capture, populated by the TCB0 capture ISR; read by AVCLan_Measure.
+extern volatile uint16_t pulsewidth;
+extern volatile uint8_t pulse_count;
+extern volatile uint16_t period;
+#endif
+
+#endif // AVCLAN_PHY_H