Intel Hex Format, Data Record, Xxxx | Multi-Tech Systems MT3334SMI

Appendixes

3.3.The packets sent to the modem must be presorted by address and aligned on 128 byte boundaries (ie. each packet must start on an address that is a multiple of 128).

3.4.The packets should also be a minimum of 128 bytes with the non-programmed bytes set to the hex value of FF.

3.5.The packets sent to the modem must not span a 4K boundary (ie. start the packet before it and go over the boundary in the middle of the packet).

3.6.The 10 millisecond delay between M’s at the beginning of the handshake is so that the modem can sync up to the start bit. If the M’s are sent one right after another, a data bit might be mistaken as a start bit.

3.7.Multi-Tech firmware files are in Intel Hex Format and must be read in and formatted into 128- 4096 byte blocks before being sent to the modem.

Refer to the Intel Hex Format section below for information about the Intel Hex Format.

Intel Hex Format

An Intel Format Hex File is a text file consisting of “records”, one per line, that start with a “:” character and include only digits 0-9 and letters A-F. There are three different record types: Extended Address Records, Data Records and End of File Records.

Data records contain the actual data that is to be programmed into a device. The address contained in the data record needs to be combined with an extended address (by adding the extended address shifted four bits left to the data record address) to determine the actual programming address for the data. If no extended address record is before a given data record in the file, then the extended address value is assumed to be zero.

The record types are described below:

Data Record

Char Pos	Field Type	Value	Description
1	Record Start	“:”
2-3	Data Byte Count	“NN”	Maximum value is FF (which is 255 data
			bytes).
			Typical is 20h which causes the hex record
			to fit in 80 columns.
4-7	Address	“XXXX”	Lower 16 bits of 20 bit address, most
			significant byte first. This must be added to
			Extended Address left shifted four bits.
Char Pos	Field Type	Value	Description
8-9	Record Type	“02”	Data Record
10+N	Data Bytes	“YY..YY”	The data bytes in hex. Each byte is two
			characters.
NN+1,2	Checksum	“ZZ”	Zero minus the two’s complement addition
			of all data hex values.
NN+3,4	End of Line	“\r\n”	Carriage Return followed by a Line Feed

Example Data Record in Intel Format

:2000A0005BB66DDBB66CD8B060C183060D1B366DDBB66DDBB76FDFBF7EFDFBF6EDDBB66DD4

MT3334SMI

Appendixes

Intel Hex Format

Data Record

“XXXX”