Add ~empty implementation of HAL for pico2

src/avclan/target/pico2/phy.cc

@@ -0,0 +1,53 @@
+#include "hal/phy.h"
+#include "avclan.h"
+
+using namespace avclan;
+using enum detail::Error::Read;
+using enum detail::Error::Send;
+
+extern "C" void phy_init() {}
+
+extern "C" void phy_mute(bool mute) {}
+
+extern "C" bool phy_is_muted() { return true; }
+
+extern "C" bool phy_active() { return false; }
+
+extern "C" void phy_guard_enter() {}
+
+extern "C" void phy_guard_leave() {}
+
+extern "C" Read phy_read_startbit() { return BAD_STARTBIT; }
+
+extern "C" Send phy_send_startbit() { return MUTED; }
+
+extern "C" Send phy_read_ack() { return MUTED; }
+
+extern "C" void phy_send_ack() {}
+
+extern "C" void phy_send_bit(Bit bit) {}
+
+extern "C" Bit phy_send_bits_u8(const uint8_t *bits, int8_t len) {
+  return Bit::bit_zero;
+};
+
+extern "C" Bit phy_send_bits_u16(const uint16_t *bits, int8_t len) {
+  return Bit::bit_zero;
+};
+
+extern "C" Bit phy_send_byte(const uint8_t *byte) { return Bit::bit_zero; };
+
+extern "C" Bit phy_read_bits_u8(uint8_t *bits, uint8_t len) {
+  return Bit::bit_zero;
+};
+
+extern "C" Bit phy_read_bits_u16(uint16_t *bits, int8_t len) {
+  return Bit::bit_zero;
+};
+
+extern "C" Bit phy_read_byte(uint8_t *byte) { return Bit::bit_zero; };
+
+#if !defined(NDEBUG) && defined(MEASURE_BUS)
+// Sample and dump bus bit timing over the serial link (REPL `M`).
+void phy_measure(void);
+#endif