C509-L_97 Datasheet, PDF (253/290 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

Bootstrap Loader
C509-L
10.4.1.1 Header Block Definition
The header block from the host, which contains the mode number and additional data to start the
selected operating mode, is a normal transfer block with the block type HEADER (00H) and a fixed
length of eight bytes (including the attached checksum of the transfer block). Figure 10-10 shows
the general structure of this header block is shown below.
Format Item
mode
startaddress
XXH
Description
This field contains the number of the operating mode:
00H Load custom program into the XRAM memory.
01H Jump to the XRAM memory at the specified
address startaddress.
02H Calculate the checksum of a specified part of the
external FLASH memory which is defined by
startaddress and datalength.
03H Jump to the FLASH memory at the specified
address startaddress.
This 16-bit address defines the start address either in
XRAM or in ext. FLASH memory. The first byte to be
transmitted is the high order byte of the 16-bit address.
These bytes have a different meaning depending on the
mode byte of a header block. The detailed definition of
these bytes is given in figures 10-11, 10-18, 10-21, and
10-24.
Figure 10-10
Structure of the HEADER Block
Semiconductor Group
10-15
1997-10-01