Linux – lpc1343 upload firmware via UART bluetooth module from linux

A bit of background first: the distinction between incoming and outgoing RFCOMM (Bluetooth stack protocol for virtual COMs) ports is necessary because it's always one of the communicating devices that initiates the connection (a bit similar to TCP sockets - where you have server and client).

• The outgoing COM port is used when the PC initiates the connection to the remote device (opening the port initiates RFCOMM connection to the remote device).
• The incoming COM port is used when the remote device initiates the connection.

Once the connection is opened it is bidirectional, regardless of the type.

That said, this Bluetooth module supports both master and slave mode (see manual chapter 2), that's why it advertises 2 RFCOMM/SPP ports, I guess. If you want PC to initiate the connection, use COM6, otherwise use COM7.

Why you see no echo in PuTTY? By default there's no local echo, and you actually shouldn't see any characters you type (unless you short UART_RX to UART_TX, or have some real device attached there to communicate with). The module itself is transparent (in the data mode, that is).

Also, baud rate etc. shouldn't really matter for Blueooth connection - note, that chapter 3.2 refers to configuring the device via physical serial port (UART_RX/TX pins, i.e. from the device side), while 3.3 describes configuring over virtual port (i.e. from the PC side). I somehow feel you're confusing the module sides ;)

This excerpt from the manual is quite important:

To connect to FireFly, browse for services, you should see: “SPP” profile with a virtual COM port. Open this virtual COM port to create a Bluetooth connection. Once connected, the device will be in data mode allowing data to flow in both directions as if the serial port were locally attached to the PC. The device must be in command mode for configuration and programming. To enter command mode type “$$$” (three dollar signs) from either the remote Bluetooth connection or the local serial port connection. You must enter command mode within 60 seconds (configurable by setting the config timer).

Cool module, btw!

This label is in ROM, and cannot be modified as far as I know. Only NXP can change this in their production process - but they need good reason ($$$$$) to do this.

The only thing you could do is to write your own boorloader. But given the small RAM (8k) and Flash (32k) of the device, this will be problematic, too - unless you have much space free in Flash.