UM11029
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2017. All rights reserved.
User manual
Rev. 1.0 — 16 June 2017
34 of 515
NXP Semiconductors
UM11029
Chapter 5: LPC84x ISP and IAP
5.5.15 ReadUID
5.5.16 Read CRC checksum
Get the CRC checksum of a block of RAM or flash. CMD_SUCCESS followed by 8 bytes
of CRC checksum in decimal format.
The checksum is calculated as follows:
CRC-32 polynomial: x32 + x26 + x23 + x22 + x16 + x12 + x11 + x10 + x8 + x7 + x5 + x4 +
x2 + x + 1
Seed Value: 0xFFFF FFFF
5.5.17 Read flash signature
Get the signature for the flash memory, using an internal flash signature generator (see
Chapter 6 “LPC84x Flash signature generator”
). When CRP1 is enabled, only the
signature of the entire flash can be read and no parameters can be passed.
Table 32.
USART ReadUID command
Command
N
Input
None
Return Code
CMD_SUCCESS followed by four 32-bit words of a unique serial number in ASCII format. The word sent at
the lowest address is sent first.
Description
This command is used to read the unique ID.
Table 33.
USART ISP Read CRC checksum command
Command
S
Input
Address:
The data are read from this address for CRC checksum calculation. This address must be on a
word boundary.
Number of Bytes:
Number of bytes to be calculated for the CRC checksum; must be a multiple of 4.
Return Code
CMD_SUCCESS followed by data in decimal format |
ADDR_ERROR (address not on word boundary) |
ADDR_NOT_MAPPED |
COUNT_ERROR (byte count is not a multiple of 4) |
PARAM_ERROR |
CODE_READ_PROTECTION_ENABLED
Description
This command is used to read the CRC checksum of a block of RAM or flash memory. This command is
blocked when code read protection is enabled.
Example
"S 33587200 4<CR><LF>" reads the CRC checksum for 4 bytes of data from address 0x0200 8000.
If checksum value is 0xCBF43926, then the host will receive:
"3421780262 <CR><LF>"