rs232.h

Sirf/Centrality公司GPS平台AtlasIII芯片AT640的Nboot源码

#ifndef _RS232_H_
#define _RS232_H_

#ifndef _INC_PMSG
#define _INC_PMSG

#ifdef __cplusplus
extern "C" {
#endif

#define SERIAL_BUF_AND	0x7f
#define SERIAL_BUF_LEN	0x80

// Maximum length of data field in a packet is 248 bytes, which yields in 254 total packet length. 
#define P_MAX_DATA_LENGTH	2048
//#define P_MAX_PACKET_LENGTH	2054

// Elementary Units of the Protocol
#define P_NUL		0x00	// Initialization Byte 
#define P_ENQ		0x05	// Action Complete Notification
#define P_ACK		0x06	// Positive Achnowledgement
#define P_DC1		0x11	// Unable to Execute Command
#define P_NAK		0x15	// Negative Acknowledgement, also Camera Signature  
#define P_END		0xff	// Termination Byte 

// Packet - Variable length sequence of bytes. Known packet types are in the following:
#define P_DATA_UNFINISHED	0x02	// Data packet that is not last in sequence 
#define P_DATA				0x03	// Data packet that is last in sequence 
#define P_CMD				0x1b	// Command packet 

/*
Packet structure as the following:
Offset	Length		Meaning 
0		1			Packet type 
1		1			Packet subtype/sequence 
2		2			Length of data 
4		variable	Data 
-2		2			Checksum 
*/

// Packet subtype
// Command packet has subtype 0x43 or 0x53. Only the first command packet in a session has subtype 0x53. 
#define P_CMD_FIRST		0x53
#define P_CMD_NORMAL	0x43

// Data packets that are sent in responce to a single command are numbered starting from zero. 
// If all requested data fits in one packet, it has type 0x03(P_DATA) and sequence 0. 

/* 
Command is a sequance of bytes sent in the data field of a command packet. 
Command format and codes are as follows:
Offset	Length		Description 
0		1			Command code 
1		1			Register number or subcode 
2		variable	Optional argument 
*/

// Five command codes are known:	Argument	Description
#define P_CMD_SET_REG	0		//	int32		Set value of integer register 
#define P_CMD_GET_REG	1		//	none		Read value of integer register 
#define P_CMD_ACTION	2		//	vdata		Take action unrelated to registers 
#define P_CMD_SET_VDATA	3		//	vdata		Set value of vdata register 
#define P_CMD_GET_VDATA	4		//	none		Read value of vdata register 

// The following registers are known:		Type	R/W	Description 
// The following registers are known:		Type	
#define P_CMD_CUR_IMG_TYPE			1	//	int32	
#define P_CMD_NAND_CS				2	//	int32	
#define P_CMD_BOOT_STAGE			3	//	int32	
#define P_CMD_FRAME_LEN				4	//	int32	
#define P_CMD_CUR_IMG_LENGTH		5	//	int32

// For command 2 (P_CMD_ACTION), the second byte is action code not register number. The following action codes are known:
//									Code	Argument			Description 
#define P_ACTION_WRITE_IMG			0	//	single zero byte	
#define P_ACTION_UPDATE_TOC			1	//	single zero byte	
#define P_ACTION_OPEN_DATA_PIPE		2	//	single zero byte	
#define P_ACTION_CLOSE_DATA_PIPE	3	//	single zero byte	

void DoRS232(void);

void Rs232Init(void);
void Rs232Handshake(void);
unsigned char Rs232GetChar(void);
void Rs232PutChar(char c);
void Rs232GetChars(void);

#ifdef __cplusplus
}
#endif

#endif

#endif//#ifndef _RS232_H_