Servo - September 2010

use the USB10 SPI portal and digital I/O lines to program the AVR of a nesting Wasp. The USB10 programming function is supported by a PC application called USB10Prog which is a free download from the SOC Robotics website.

What would ANY microcontroller project be without LEDs? As you’ve probably already figured out, the l-led command allows us to illuminate or extinguish the red and green LEDs that are indigenous to the USB10.

Like the l-led command, b-boot is pretty obvious as to what the function performs. When b-boot is selected, the boot routine loaded in the high memory of the AT90USB162 kicks off. A new program is loaded with the help of an Atmel application called FLIP.

The Ferret control program does all of this and NEVER backs up into a corner.

Where’s the Code?

It’s already written. The Wasp Data Logger application not only contains data logger routines, it contains separate C modules that enable and exercise the AT90USB162’s SPI portal, TWI module, UART, and I2C functions. You’ll also find a C module that initializes all of the Wasp hardware. There’s even C code for a monitor and the interrupt handlers. If that’s not enough canned C code for you, here’s an excerpt from the utilities module that writes data to the Wasp EEPROM:

// Function to initiate an EEPROM write
// writes the specified data byte to the
specified location
// this will fail if the EEPROM is not ready!
void RTEEPROMwrite(int location, unsigned char
databyte)
{
unsigned char savedSREG;
EEAR = location; // set address
EEDR = databyte; // set data
savedSREG = SREG; // keep setting so
 // it can be
 // restored
 // disable interrupts
 // set “write enable” bit
 // set “write” bit
 // restore SREG
CLI();
EECR |= BIT(EEMWE);
EECR |= BIT(EEWE);
SREG = savedSREG;
EEAR = 0;
}
// function to test if the EEPROM is ready
// for a read or write operation
// returns non zero if ready, zero if not
// ready
unsigned char RTEEPROMReady(void)
{
return !(EECR & 0x02);

58 SERVO 09.2010

I included the EEPROM ready code to show you that everything you need to interface your C code to a Wasp is most likely already contained in some form or fashion within the data logger application modules. There are even C routines in the data logger modules that can be called to blink the LEDs.

To make the assimilation of the canned Wasp C routines easy, the entire Wasp Data Logger application was written using ImageCraft ICCVX for AVR and Atmel’s AVR Studio. AVR Studio is a free download and the ImageCraft C compiler is as inexpensive as C compilers go. ImageCraft also offers a 45 day trial period to allow you to fall in love with their AVR C compiler. SOC Robotics offers a huge bang for the firmware buck, as well. You can download the Wasp Data Logger application, the AT90USB162 Bootloader, the UB10Prog programmer application, and Ferret control program for free from the SOC Robotics website.