Nuts and Volts - September 2011

// Configure IOMUX
// GPIO Port A 0 to pin 39 as Output.
vos_iomux_define_output(39,
IOMUX_OUT_GPIO_PORT_A_0); // LED1#
// GPIO Port A 1 to pin 40 as Output.
vos_iomux_define_output(40,
IOMUX_OUT_GPIO_PORT_A_1); // LED2#
// GPIO Port A 2 to pin 41 as Output.
vos_iomux_define_output(41,
IOMUX_OUT_GPIO_PORT_A_2); // PWREN#
// GPIO Port C 0 to pin 24 as Output.
vos_iomux_define_output(24,
IOMUX_OUT_GPIO_PORT_C_0); // DB4
// GPIO Port C 1 to pin 25 as Output.
vos_iomux_define_output(25,
IOMUX_OUT_GPIO_PORT_C_1); // DB5
// GPIO Port C 2 to pin 26 as Output.
vos_iomux_define_output(26,
IOMUX_OUT_GPIO_PORT_C_2); // DB6
// GPIO Port C 3 to pin 27 as Output.
vos_iomux_define_output(27,
IOMUX_OUT_GPIO_PORT_C_3); // DB7
// GPIO Port C 4 to pin 28 as Output.
vos_iomux_define_output(28,
IOMUX_OUT_GPIO_PORT_C_4); // RS
// GPIO Port C 5 to pin 29 as Output.
vos_iomux_define_output(29,
IOMUX_OUT_GPIO_PORT_C_5); // E

■ SCREENSHOT 2. The FTDI FT_PROG utility is a free download from the FTDI site. This utility reveals what type of FTDI IC is plugged into the USB portal and what it is programmed to do. You can also use this utility to program an attached FTDI FT232RL device.

ride on the Vinco’s unused PORTC pins. I used the VNC2 IOMux config utility to add the PORTC LCD definitions. Everything we did to get PORTA operational is also done for PORTC within the main function.

The Vinculum-II API provides a host driver that is written specifically to drive FTDI-based slave devices like the FT232R in our ProBee ZU10 module. Once the core USB host is established, the FT232 host driver is logically attached to it in the ProBee ZU10 application code. We initialize the FT232R host driver in the main function:

// Initialize USB Host FT232 Driver
usbHostFt232_init(VOS_DEV_USBHOST_FT232);

The thread called firmware holds all of the application code and falls under the control of the VOS scheduler. You can operationally think of the Vinculum-II firmware function as a standard C main function. The major difference is that there can be multiple thread functions in a Vinculum-II application code set. The ProBee ZU10 application contains a single thread. Here’s how we created it:

//***********************************************
//* VOS APPLICATION THREADS
//***********************************************
vos_tcb_t *tcbFIRMWARE;

tcbFIRMWARE = vos_create_thread_ex(20, 4096,
firmware, “Application”, 0);

As you would expect, vos_tcb_t is a structure located in the vos.h file. Our thread (firmware) is tied to an instance of vos_tcb_t via the pointer tcbFIRMWARE. Now that we have a place to run some code, we can start the scheduler:

vos_start_scheduler();

The main function can now be jettisoned to endless loop land.

THE APPLICATION CODE

The addition of the active-low PWREN# gives us a programmable way to apply USB host power to the ProBee ZU10 via the Type A USB portal. The LCD will Take a look inside of the firmware thread. You will see that all of the USB host and GPIO control blocks are instantiated inside of the firmware braces. You will also find that the necessary devices are opened and their associated handles are assigned with the confines of the firmware thread. Hardware and firmware

■ PHOTO 3. There is a complete ZigBee radio behind that USB connector. All we have to do is figure out how to talk to it without plugging the ProBee ZU10 into a PC.