Add Raspberry Pi Pico port (#1232)

* Add Raspberry Pi Pico port
- Adds BACnet/IP with abstracted network layer
- Adds BACnet MS/TP support using RS485/UART
- Includes README with examples

* Add Pico 2 MS/TP demo, CI, and docs

ports/pico/bvlc-pico.h

@@ -0,0 +1,36 @@
+/**
+ * @file
+ * @authors Miguel Fernandes <miguelandre.fernandes@gmail.com> Testimony Adams
+ * <adamstestimony@gmail.com>
+ * @date 6 de Jun de 2013
+ * @brief BACnet Virtual Link Control for Pico
+ */
+
+#ifndef BVLC_PICO_H
+#define BVLC_PICO_H
+
+#include <stdint.h>
+#include "bacnet/datalink/bvlc.h"
+
+#define BACNET_BVLC_RESULT uint8_t
+#define BACNET_BVLC_FUNCTION uint8_t
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Maximum packet size for BACnet/IP */
+#ifndef BIP_MPDU_MAX
+#define BIP_MPDU_MAX 1506
+#endif
+
+uint16_t bvlc_for_non_bbmd(
+    uint8_t *addr, uint16_t *port, uint8_t *npdu, uint16_t received_bytes);
+
+BACNET_BVLC_FUNCTION pico_bvlc_get_function_code(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* BVLC_PICO_H */