Datasheet

I2C Bootloader

Document Number: 001-13258 Rev. *J Page 9 of 39

To translate from Blocks to absolute addresses, multiply: Abs_addr = block_number X Block Size. Block_0

starts at addr 0, Block_n starts at address n x Block_size. All blocks are delimited in hex for the bootloader

parameters, so a hex address can be obtained by multiplying by 0x40 (64-byte blocks) or 0x80 (128-byte

blocks).

Hex output files contain an absolute address for each line. Regardless of the block size of the device in

question (0x40/0x80), the hex output file breaks the code into lines of 64(d)/0x40 bytes per line. As a

result, for a 64 byte block device each line represents a block of code. For a 128 byte block device, two

lines from the hex file go into a block (because block 0 starts at address 0, 128 byte blocks must be

ALWAYS considered to have an “even" half representing the lower (address) half and an “odd" half

representing the upper (address) half).

See a hex file and become familiar with the flash block size for the part that you are working with.

Host Application Debugging

An application with a built-in bootloader may be difficult to debug. As a result, there are additional

adjustments that can be made within the BootLdrI2C User Module files. These are contained in the file

BootLdrI2C_Bootloader.inc. This file has a section that contains the following equates:

BOOT_TIMEOUT: EQU 40 ;set to zero to make timeout infinite

CHECKSUM_ON_CKSUMBLK: EQU 1 ;Apply a checksum to the checksum block

;(adds compile steps and code to verify)

The BOOT_TIMEOUT equate enables you to lengthen, shorten, or make infinite code that timeouts if no

communication is received from a host after your command calls the bootloader. This may be useful when

developing or debugging the host application.

The second equate controls the use of the checksum inside the checksum block. If this equate is set to 0,

no verification is done on the checksum inside the checksum block. A checksum verification is still

performed on the entire user application area as defined in the user module parameters.

Placement

The I2CHW User Module allows two choices of SCL and SDA P1[5]/P1[7] or P1[0]/P1[1] and does not

require any digital or analog PSoC blocks. There are no placement restrictions. Placement of multiple I

modules is not possible because the I

C module uses a dedicated PSoC resource block and interrupt.