/* UMP logger v2 (PM35), independent of PM67 and SET protocol v2.
 * Octets use 16-bit storage: C28x has CHAR_BIT=16 and no uint8_t.
 * All lengths below count wire octets or register words, never sizeof bytes.
 */
#ifndef UMP_PROTOCOL_H
#define UMP_PROTOCOL_H
#include <stdint.h>
#include <stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
#define UMP_BASE 0x1000U
#define UMP_DATA 0x1010U
#define UMP_LIVE 0x1100U
#define UMP_MARKER 0x1F00U
#define UMP_MAX_WORDS 124U
#define UMP_RTU_CAPACITY 253U
typedef uint16_t ump_octet;
/* Called under caller's snapshot lock. write returns 1 on success, 0 otherwise. */
typedef struct {
    void *context;
    uint16_t (*read)(void *context, uint16_t address);
    int (*write)(void *context, uint16_t address, uint16_t value);
} ump_backend;
/* Returns Modbus exception 0/1/2/3. CAN has stricter whole-block reads. */
unsigned ump_validate(unsigned function, uint16_t address, uint16_t value, int can);
/* reply capacity is >=124 words. Errors and writes return address/value echo. */
unsigned ump_prepare(const ump_backend *backend, unsigned function,
    uint16_t address, uint16_t value, int can, uint16_t *reply, unsigned *error);
uint16_t ump_crc(const ump_octet *data, size_t count);
/* Mode 1..16; kind 0=request, 1=normal telemetry, 2=logger reply; invalid ->0. */
uint32_t ump_can_id(unsigned mode, unsigned kind);
/* Returns 0 for non-service frames, malformed size, or zero token. */
unsigned ump_can_request(const ump_backend *backend, const ump_octet *request,
    size_t size, uint16_t *reply, unsigned *token, unsigned *error);
/* count must be an even number 2..124; index counts pairs. Returns 8 or 0. */
unsigned ump_can_fragment(const uint16_t *words, unsigned count, unsigned index,
    unsigned token, unsigned error, ump_octet *reply);
/* Complete RTU frame only, after UART framing. Ignores bad CRC/foreign address.
 * Caller provides >=253 octets; no writes occur on insufficient capacity.
 * Device address 1..247; no broadcasts or legacy padding in this extension.
 */
size_t ump_rtu(const ump_backend *backend, unsigned device,
    const ump_octet *request, size_t size, ump_octet *reply, size_t capacity);
/* Response for an already CRC-checked/framed request (legacy UART receiver). */
size_t ump_rtu_response(const ump_backend *backend, unsigned device, unsigned function,
    uint16_t address, uint16_t value, ump_octet *reply, size_t capacity);
/* Serialize a captured reply after releasing the snapshot lock. Returns 0 on
 * invalid count/capacity; error replies need no words. */
size_t ump_rtu_encode(unsigned device, unsigned function, unsigned error,
    const uint16_t *words, unsigned count, ump_octet *reply, size_t capacity);
#ifdef __cplusplus
}
#endif
#endif