UM10429
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© NXP B.V. 2010. All rights reserved.
User manual
Rev. 1 — 20 October 2010
151 of 258
NXP Semiconductors
UM10429
Chapter 17: LPC1102 Flash memory programming firmware
Important: any CRP change becomes effective only after the device has gone
through a power cycle.
Remark:
The LPC1102 does not provide an ISP entry pin to be monitored at reset. For all
three CRP levels, the user’s application code must provide a flash update mechanism
which reinvokes ISP by defining a user-selected PIO pin for ISP entry.
Table 148. Code Read Protection options
Name
Pattern
programmed in
0x0000 02FC
Description
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 cannot access RAM below 0x1000
0300.
•
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. No ISP access.
Table 149. Code Read Protection hardware/software interaction
CRP option
User Code
Valid
SWD enabled
LPC1102 enters
ISP mode
partial flash
update in ISP
mode
None
No
Yes
Yes
Yes
None
Yes
Yes
No
NA
CRP1
Yes
No
No
NA
CRP2
Yes
No
No
NA
CRP3
Yes
No
No
NA
CRP1
No
No
Yes
Yes
CRP2
No
No
Yes
No
CRP3
No
No
Yes
No