We've put a new version of the library live (version 23). The highlights are:

• CAN fixes
• Serial transmit interrupt added
• I2C low level routines added

CAN

A number of CAN fixes have been implemented. Firstly, the frequency() method has been improved, and now should manage most frequencies requested. Secondly, self-reception has been turned off. Finally, the CAN interface pins which are not brought out on mbed, are now capable of being enabled in the library.

Serial

You can now attach a function to a Serial object which is triggered when the transmit buffer is empty. The attach() method has been updated with a new second paramter 'type', which can be set to Serial::RxIrq or Serial::TxIrq (defaults to RxIrq for backward compatability). You can have a receive interrupt routine defined, a transmit interrupt routine, or both (or neither).

I2C

Due to popular request, the I2C class now has low level byte-access control. This is of the form start(), stop(), and overloaded read() and write() methods. The new read() takes a parameter which indicates whether to ACK or NoACK, and the new write() returns a 1 if the byte was ACK'd, and a 0 if it was NACK'd. The old read() and write() still operate as before - these still have merit as they handle the internal state machine of the I2C block in the LPC1768/2368.

// Talk to the CMPS03 I2C digital compass
#include "mbed.h"

int main() {
    I2C cmp(p28, p27);				// I2C Compass

    printf("Reset!\n");
    cmp.frequency(100000);

    while(1) {
        cmp.start();				// Start condition
        cmp.write(0xC0);			// Address 0xC0 write
        cmp.write(0x02);			// Register 2
        cmp.start();				// Repeated start
        cmp.write(0xC1);			// Address 0xC0 read
        int d = cmp.read(I2C::ACK) << 8;	// Read upper 8 bits, with ACK
        d += cmp.read(I2C::NoACK);		// Read lower 8 bits, no ACK
        cmp.stop();				// Stop condition
        printf("%d\n", d);			// Print result
        wait(0.5);
    }
}

Updating to the new Library

As usual, to get these updates for existing programs, simply click on the mbed library in your compiler project and choose "Update to latest revision!". New programs will automatically pull it in.

Any problems, suggestions or thumbs ups, please tell us in the Bugs/Suggestions forum!