LPC3152 Developers Kit - User’s Guide
Page 31
Copyright 2012 © Embedded Artists AB
Select the desired COM port number under the
Advanced
settings dialog. NXP’s FLASH Utility
program (for ISP program download) needs, for example, a COM port number between 1 and 5. Very
often the COM port number is selected but the USB Serial Port is higher than this, therefore this need
to be changed manually.
It is common that all COM ports with low numbers are listed as occupied, but test to change to a low
number anyway. Very often it is no problem at all to do so.
Figure 13 – Advanced USB Serial Port Properties Dialog
Finally it is time to test if you have successfully installed and configured the USB Serial Port. Start a
terminal program, for example TeraTerm. Connect to the correct COM port, with 115200 bits per
second, 8N1, no flow control.
5.2.1
USB Driver Behavior
Sometimes the USB COM port does not enumerate properly when the board in connected to the PC.
This is a known “feature” of the USB driver. If you experience this problem, just unplug the board
shortly and then plug in again. A new COM port that can be accessed properly should be created the
second time.
This problem may occur after every time you start (i.e., power cycle) your PC.
5.3
Booting
The processor will start its code execution from an internal ROM, containing the boot code. This code
determines the boot mode by sampling the reset state of the pins GPIO0, GPIO1 and GPIO2. Multiple
boot options are supported:
Booting from different sources; SPI flash, NAND flash, SD/SDHC/MMC cards, UART and
USB (DFU class) interfaces
Option to perform CRC32 checking on the boot image
The boot code copies/downloads the boot image to internal SRAM at location 0x1102 9000 and jumps
to that location (sets ARM’s program counter register to 0x1102 9000) after image verification. Hence
the boot images should be compiled with entry point at 0x1102 9000. The boot code can handle boot
images up to 128 kByte in size on the LPC3152. For larger applications, the booting has to be done in
more steps, i.e., a second stage boot loader has to be added.
Note that the boot code initializes the MMU (Memory Management Unit) with a pre-defined MMU table.
This table is 16 kByte in size, so systems with RAM constraints (or small and simple systems) can
COM Port
Number Setting
