NXP Semiconductors LPC24XX UM10237 - Manual (Page 709)

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User manual Rev. 04 — 26 August 2009 709 of 792
NXP Semiconductors
UM10237
Chapter 31: LPC24XX On-chip bootloader for flashless parts
7.3 Compare <address1> <address2> <no of bytes>
7.4 Reinvoke ISP
7.5 IAP Status Codes
Table 646. IAP Compare command
Command Compare
Input Command code: 56
10
Param0(DST): Starting RAM address of data bytes to be compared. This address
should be a word boundary.
Param1(SRC): Starting RAM address of data bytes to be compared. This address
should be a word boundary.
Param2: Number of bytes to be compared; should be a multiple of 4.
Return Code CMD_SUCCESS |
COMPARE_ERROR |
COUNT_ERROR (Byte count is not a multiple of 4) |
ADDR_ERROR |
ADDR_NOT_MAPPED
Result Result0: Offset of the first mismatch if the Status Code is COMPARE_ERROR.
Description This command is used to compare the memory contents at two locations.
The result may not be correct when the source or destination includes any
of the first 64 bytes starting from address zero. The first 64 bytes can be
re-mapped to RAM.
Table 647. Reinvoke ISP
Command Compare
Input Command code: 57
10
Return Code None
Result None.
Description This command is used to invoke the bootloader in ISP mode. It maps boot
vectors, sets PCLK = CCLK / 4, configures UART0 pins Rx and Tx, resets
TIMER1 and resets the U0FDR (see
Section 16–4.12 ). This command may be
used when a valid user program is present in the external memory and the P2.10
pin is not accessible to force the ISP mode. The command does not disable the
PLL hence it is possible to invoke the bootloader when the part is running off the
PLL. In such case the ISP utility should pass the CCLK (crystal or PLL output
depending on the clock source selection
Section 4–3.1.1 ) frequency after
autobaud handshake.
Another option is to disable the PLL and select the IRC as the clock source before
making this IAP call. In this case frequency sent by ISP is ignored and IRC and
PLL are used to generate CCLK = 14.748 MHz.
Table 648. IAP Status Codes Summary
Status
Code Mnemonic Description
0 CMD_SUCCESS Command is executed successfully.
1 INVALID_COMMAND Invalid command.
2 SRC_ADDR_ERROR Source address is not on a word boundary.