mbed

Don't understand the question;

Mbed pin 28 is P0.10 which can function as:- GPIO Port 0.10 or TXD2 or SDA2 or MAT3.0

Mbed pin 27 is P0.11 which can function as:- GPIO Port 0.11 or RXD2 or SCL2 or MAT3.1

Phyiscal pins 98 and 99 are connected to the backend Mbed IF and serial data sent out of TXD0/RXD0 are redirected via the USB. So pins 98/99 are not available for use directly but indirectly as the default serial port used for Serial(USBTX, USBRX).

See http://mbed.org/handbook/mbed-NXP-LPC1768 and you can find the Mbed schematic here

Andy,

Can I use pin 98 and pin 99 of LPC1768 to get data over USB? I connected pin98 to FT232R TX and pin99 to FT232R RX in my custom board.

I downloadloaded an equivalent hex file to LPC1768 which sends out "hello" to teraterm in mbed . but not in my custom board.

Tried to read data through a Hyperterminal. But I could see nothing on terminal in custom board.

What could be the problem? Is pin98 and 99 usable ?

Pin 98 on mbed is P0.2 TXD0

Pin 99 on mbed is P0.3 RXD0

Pin 1 on FT232 is TXD

Pin 5 on FT232 is RXD

You should connect mbed TXD0 (Pin 98) to FT232 RXD (Pin 5) and mbed RXD0 (Pin 99) to FT232 TXD (Pin 1). That should fix your problem.

Wim,

Thanks for your reply.

just before I got your reply, I experimented to use TXD2 & RXD2 of mbed as well as LPC1768 and it worked. Then I could figure out the mistake just like you mentioned above.

Still I haven't tried the TXD0 & RXD0.

I was under the impression that TXD0 and RXD0 are some thing special from all other TXD's and RXD's of mbed, as these pins are not exposed outside for the users. Is it true? or Is it exactly same like any other serial port like ( pin 9 ,10 or 27,28)?

Still I would like to know what ever programs( bin files) I devolopled using Serial pc(USBTX, USBRX) library in mbed will they work w/o problems in LPC1768 (hex converted ) if I connect TXD0 (Pin 98) to FT232 RXD (Pin 5) and RXD0 (Pin 99) to FT232 TXD (Pin 1).

TXD0,RXD0 will work like the other serial ports. It has a special function on mbed as it is connected to the mbed interface chip that converts serial to usb (much like the ftd232). The other special function of serial port 0 is that it can be used in ISP mode to download a new program. You need software like flashmagic to make that work.