esp32: replace port with PlatformIO implementation and add CI build (#1292)

ports/esp32/src/rs485.h

@@ -0,0 +1,100 @@
+/**
+ * @file
+ * @brief RS485 UART driver declarations used by BACnet MS/TP on ESP32
+ * @author Kato Gangstad
+ */
+
+#ifndef M5STAMPLC_RS485_H
+#define M5STAMPLC_RS485_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define RS485_UART_NUM UART_NUM_1
+#define RS485_BAUD_RATE 38400
+#define RS485_TX_PIN 0
+#define RS485_RX_PIN 39
+#define RS485_DIR_PIN 46
+
+/**
+ * @brief Initialize the RS485 UART peripheral
+ */
+void rs485_init(void);
+
+/**
+ * @brief Update the cached RS485 transmit-enable state
+ * @param enable true when transmit is active
+ */
+void rs485_rts_enable(bool enable);
+
+/**
+ * @brief Check whether the RS485 transmit-enable state is active
+ * @return true if transmit is active
+ */
+bool rs485_rts_enabled(void);
+
+/**
+ * @brief Read one byte from the RS485 receive FIFO when available
+ * @param data_register destination for the received byte, or NULL to probe only
+ * @return true if a byte is available
+ */
+bool rs485_byte_available(uint8_t *data_register);
+
+/**
+ * @brief Report whether an RS485 receive error is pending
+ * @return true if a receive error is detected
+ */
+bool rs485_receive_error(void);
+
+/**
+ * @brief Send a block of RS485 bytes
+ * @param buffer transmit buffer
+ * @param nbytes number of bytes to send
+ */
+void rs485_bytes_send(const uint8_t *buffer, uint16_t nbytes);
+
+/**
+ * @brief Get the configured RS485 baud rate
+ * @return baud rate in bits per second
+ */
+uint32_t rs485_baud_rate(void);
+
+/**
+ * @brief Set the RS485 baud rate
+ * @param baud baud rate in bits per second
+ * @return true if the baud rate was applied
+ */
+bool rs485_baud_rate_set(uint32_t baud);
+
+/**
+ * @brief Get the elapsed silent time on the RS485 bus
+ * @return milliseconds since the last bus activity
+ */
+uint32_t rs485_silence_milliseconds(void);
+
+/**
+ * @brief Reset the RS485 silence timer
+ */
+void rs485_silence_reset(void);
+
+/**
+ * @brief Get the number of transmitted RS485 bytes
+ * @return transmitted byte count
+ */
+uint32_t rs485_bytes_transmitted(void);
+
+/**
+ * @brief Get the number of received RS485 bytes
+ * @return received byte count
+ */
+uint32_t rs485_bytes_received(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif