Move PM35 protocol into shared C core

c/set-protocol/include/periph28335.h

@@ -0,0 +1,68 @@
+/**
+ * @file periph28335.h
+ * @brief Shared PM35/TMS320F28335 register protocol.
+ *
+ * The protocol is independent from PM67/TMS320F2812 CAN and RS channels.
+ * It implements the direct RS232/485 register terminal used by PM35.
+ */
+#ifndef PERIPH28335_H
+#define PERIPH28335_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define PERIPH28335_REGISTER_COUNT 128U
+#define PERIPH28335_REQUEST_SIZE 8U
+#define PERIPH28335_COMMAND_COUNT 17U
+
+typedef enum {
+    PERIPH28335_OK = 0,
+    PERIPH28335_ERROR_ARGUMENT = -1,
+    PERIPH28335_ERROR_RANGE = -2,
+    PERIPH28335_ERROR_LENGTH = -3,
+    PERIPH28335_ERROR_CRC = -4,
+    PERIPH28335_ERROR_HEADER = -5,
+    PERIPH28335_ERROR_CAPACITY = -6
+} periph28335_status_t;
+
+uint16_t periph28335_crc16_modbus(const uint8_t *data, size_t size);
+
+size_t periph28335_append_crc(const uint8_t *payload, size_t payload_size,
+                              uint8_t *output, size_t output_size);
+
+size_t periph28335_build_read_registers(
+    uint8_t controller, uint16_t start, uint16_t count,
+    uint8_t *output, size_t output_size);
+
+size_t periph28335_build_write_register(
+    uint8_t controller, uint16_t address, uint16_t value,
+    uint8_t *output, size_t output_size);
+
+size_t periph28335_build_command(
+    uint8_t controller, uint8_t command_index,
+    uint8_t *output, size_t output_size);
+
+size_t periph28335_expected_read_response_size(uint16_t count);
+
+int periph28335_decode_read_response(
+    const uint8_t *data, size_t size, uint8_t controller, uint16_t count,
+    uint16_t *output, size_t output_count);
+
+int periph28335_validate_write_response(
+    const uint8_t *response, size_t response_size,
+    const uint8_t *request, size_t request_size);
+
+size_t periph28335_project_count(void);
+const char *periph28335_project_name(size_t project_index);
+const char *periph28335_command_name(size_t project_index,
+                                     size_t command_index);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PERIPH28335_H */