Datasheet

UM10398 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2014. All rights reserved.
User manual Rev. 12.3 — 10 June 2014 421 of 547
NXP Semiconductors
UM10398
Chapter 26: LPC111x/LPC11Cxx Flash programming firmware
Table 372. Code Read Protection options
Name Pattern
programmed in
0x0000 02FC
Description
NO_ISP 0x4E69 7370 Prevents sampling of pin PIO0_1 for entering ISP mode. PIO0_1 is
available for other uses.
CRP1 0x12345678 Access to chip via the SWD pins is disabled. This mode allows partial
flash update using the following ISP commands and restrictions:
• Write to RAM command should not access RAM below 0x1000
0300. Access to addresses below 0x1000 0200 is disabled.
• Copy RAM to flash command can not write to Sector 0.
• Erase command can erase Sector 0 only when all sectors are
selected for erase.
• Compare command is disabled.
• Read Memory command is disabled.
This mode is useful when CRP is required and flash field updates are
needed but all sectors can not be erased. Since compare command
is disabled in case of partial updates the secondary loader should
implement checksum mechanism to verify the integrity of the flash.
CRP2 0x87654321 Access to chip via the SWD pins is disabled. The following ISP
commands are disabled:
• Read Memory
• Write to RAM
• Go
• Copy RAM to flash
• Compare
When CRP2 is enabled the ISP erase command only allows erasure
of all user sectors.
CRP3 0x43218765 Access to chip via the SWD pins is disabled. ISP entry by pulling
PIO0_1 LOW is disabled if a valid user code is present in flash sector
0.
This mode effectively disables ISP override using PIO0_1 pin. It is up
to the user’s application to provide a flash update mechanism using
IAP calls or call reinvoke ISP command to enable flash update via
UART.
Caution: If CRP3 is selected, no future factory testing can be
performed on the device.
Table 373. Code Read Protection hardware/software interaction
CRP option User Code
Valid
PIO0_1 pin at
reset
SWD enabled LPC111x/
LPC11Cxx
enters ISP
mode
partial flash
update in ISP
mode
None No x Yes Yes Yes
None Yes High Yes No NA
None Yes Low Yes Yes Yes
CRP1 Yes High No No NA
CRP1 Yes Low No Yes Yes
CRP2 Yes High No No NA