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Philips Semiconductors
Volume 1
of the boot block are also visible in the memory region starting from the address
0x0000 0000. The reset vector contains a jump instruction to the entry point of the flash
boot loader software.
19.4.2 Criterion for valid user code
Criterion for valid user code: The reserved ARM interrupt vector location (0x0000 0014)
should contain the 2's complement of the check-sum of the remaining interrupt vectors.
This causes the checksum of all of the vectors together to be 0. The boot loader code
disables the overlaying of the interrupt vectors from the boot block, then checksums the
interrupt vectors in sector 0 of the flash. If the signatures match then the execution control
is transferred to the user code by loading the program counter with 0x0000 0000. Hence
the user flash reset vector should contain a jump instruction to the entry point of the user
application code.
If the signature is not valid, the auto-baud routine synchronizes with the host via serial port
0. The host should send a '?' (0x3F) as a synchronization character and wait for a
response. The host side serial port settings should be 8 data bits, 1 stop bit and no parity.
The auto-baud routine measures the bit time of the received synchronization character in
terms of its own frequency and programs the baud rate generator of the serial port. It also
sends an ASCII string ("Synchronized<CR><LF>") to the Host. In response to this host
should send the same string ("Synchronized<CR><LF>"). The auto-baud routine looks at
the received characters to verify synchronization. If synchronization is verified then
"OK<CR><LF>" string is sent to the host. Host should respond by sending the crystal
frequency (in kHz) at which the part is running. For example, if the part is running at 10
User manual
2.0 GB
2.0 GB - 8 kB
0.0 GB
Remark: Memory regions are not drawn to scale.
Fig 61. Map of lower memory after reset for LPC2103 with 32 kB of Flash memory
Rev. 01 — 12 January 2006
8 kB BOOT BLOCK
(BOOT BLOCK INTERRUPT VECTORS)
ON-CHIP FLASH MEMORY
ACTIVE INTERRUPT VECTORS
FROM BOOT BLOCK
UM10161
Chapter 19: Flash memory
0x7FFF FFFF
0x7FFF E000
0x0000 7FFF
0x0000 0000
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
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