UM10462
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User manual
Rev. 5.5 — 21 December 2016
391 of 523
NXP Semiconductors
UM10462
Chapter 20: LPC11U3x/2x/1x Flash programming firmware
For the LPC11U3x/2x/1x parts, the state of PIO0_3 determines whether the UART or USB
interface will be used (see
•
If PIO0_3 is sampled HIGH, the bootloader connects the LPC1Uxx as a MSC USB
device to a PC host. The LPC11U3x/2x/1x flash memory space is represented as a
drive in the host’s operating system.
•
If PIO0_3 is sampled LOW, the bootloader configures the UART serial port using pins
PIO0_18 and PIO0_19 for RXD and TXD and calls the ISP command handler.
Remark:
The sampling of pin PIO0_1 can be disabled through programming flash
location 0x0000 02FC (see
).
The use of the ISP entry pins depends on the boot loader version. See
. The
boot loader version can be obtained using the ISP or IAP commands. Also refer to the
LPC11U1x errata.
20.5 Memory map after any reset
The boot block is 16 kB in size and is located in the memory region starting from the
address 0x1FFF 0000. The bootloader is designed to run from this memory area, but both
the ISP and IAP software use parts of the on-chip RAM. The RAM usage is described
later in this chapter. The interrupt vectors residing in the boot block of the on-chip flash
memory also become active after reset, i.e., the bottom 512 bytes of the boot block are
also visible in the memory region starting from the address 0x0000 0000.
20.6 Flash content protection mechanism
The LPC11U3x/2x/1x is equipped with the Error Correction Code (ECC) capable Flash
memory. The purpose of an error correction module is twofold. Firstly, it decodes data
words read from the memory into output data words. Secondly, it encodes data words to
be written to the memory. The error correction capability consists of single bit error
correction with Hamming code.
The operation of ECC is transparent to the running application. The ECC content itself is
stored in a flash memory not accessible by user’s code to either read from it or write into it
on its own. A byte of ECC corresponds to every consecutive 128 bits of the user
accessible Flash. Consequently, Flash bytes from 0x0000 0000 to 0x0000 000F are
protected by the first ECC byte, Flash bytes from 0x0000 0010 to 0x0000 001F are
protected by the second ECC byte, etc.
Table 358. ISP entry pins for different boot loader versions
Boot loader
version
ISP entry pins
Boot modes
7.0
Pins PIO0_1 and PIO0_3 must be pulled LOW to enter
UART ISP mode.
UART only
7.1
Only pin PIO0_1 must be pulled LOW to enter UART ISP
mode. Pin PIO0_3 is don’t care.
UART only
7.4 and higher
Pins PIO0_1 and PIO0_3 must be pulled LOW to enter
UART ISP mode.
UART and USB