Datasheet

I2C Bootloader

Document Number: 001-13258 Rev. *J Page 33 of 39

Table 5. Slave Address Read Responses

For details, see the BootLoader operation flowchart at the end of this document.

Slave address write commands do not require responses, so the next two bytes of each of the slave

address write lines is an I

C prefix that the bootloader ignores. Use the Ignore_N_I2C_Prefix_Bytes

parameter to set the number of prefix bytes used in your application.

The first and third lines of the sample download record contain bootloader commands. The bootloader

commands listed in Table 6 are used:

Table 6. Bootloader Commands

All bootloader commands must be sent with the bootloader key. The bootloader ignores commands that

are not sent with the proper key. You can set the bootloader key with the Bootloader_Key parameter.

Bootloader Write Block Command

Most of the commands sent to the bootloader are write block commands. The format of each of the write

block commands is identical. The third block contains the checksum information. The format of the

checksum block is discussed in this section. Each of the other write block command transmits a 64-byte

hex record to the bootloader in five packets totalling 78 bytes (neglecting addresses and discarded

prefixes).

The first line of the write block command contains a control byte, an ignored 2-byte I

C prefix, the write

block command, the bootloader key, the block number being transmitted, and the first four bytes of data.

The block number in this example is 0x0002, which corresponds to ROM address 0x0080.

Code Meaning

0x20 Bootload mode (Success). Received 'Enter bootloader' command with valid

bootLoader Key.

0x02 Image verify error. The checksum of application and relocatable interrupt

vector areas calculated by the bootloader does not match the checksum

received from the Host.

0x04 Flash checksum error. The flash block content does not match the data

received from Host.

0x08 Flash protection error. Flash block cannot be rewritten because its flash

protection level does not allow this.

0x10 Comm checksum error. Received a packet with incorrect checksum.

0x40 Invalid bootloader key. A packet with the incorrect bootLoaderKey value was

received.

0x80 Invalid command error. Unknown command was received.

Command Meaning

FF38 Enter bootloader

FF39 Write block

FF3B Exit bootloader