Texas Instruments CC2520, User Manual

Page: 19 / 45

swru138
19/33
The USB controller communicates with the evaluation module using SPI or UART.
Note that not all of the peripherals on the board are accessible from the USB controller. It has
access to the UART RS232 interface, LCD, one LED (D6), joystick and one button (USB
button). I.e. it does not have access to the serial flash on the board.
The module connected to the EM connector has potentially access to all of the EB
peripherals. It has full access to the LCD, serial flash, four LEDs, 2 buttons, joystick and
UART RS232 interface.
Since many of the peripherals can be accessed from both the USB controller and the MCU
EM, some I/O pins can potentially be driven by two different sources. The standard firmware
running on the USB controller handles this by setting all shared I/O in three-state (high
impedance) and thus avoids conflict.
7.1 USB MCU
The USB MCU is the CC2511F32 from Texas Instruments. It is actually a Low Power
Wireless System-on-chip including a state-of-the-art 2.4 GHz radio, 32 kB in system
programmable flash, 4 kB RAM, a 12 bit ADC, timers and a USB controller. Please see
www.ti.com/cc2511 for detailed information about this controller.
7.1.1 Boot loader and standard firmware
The USB controller is programmed with a boot loader when it is shipped from the factory. The
boot loader allows programming of new code into the USB MCU via the USB cable (i.e. no
extra programmer or hardware needed). The boot loader communicates with SmartRF Studio
or SmartRF Flash Programmer.
When the USB controller starts running, it will check for a valid version of firmware in flash. If
it detects a valid application, the boot loader boots the firmware and cedes control of the
controller.
The standard firmware is used to control the RF EM and communicate with applications
running on the PC via USB.
Updating of firmware is done automatically by SmartRF Studio if it detects an old and/or
incompatible firmware version on the controller. SmartRF Studio and SmartRF Flash
Programmer also allow manual programming of the firmware. Please refer to the respective
user’s guides for detailed instructions.
It is also possible to update the firmware and boot loader on the board by using the debug
interface of the USB Controller. As this is a CC2511, use a SmartRF04EB
2
to program the
controller. Connect a 10-pin flat cable to the “Ext SoC Debug” plug (P3) on the SmartRF04EB
and to the “USB Debug” plug (P2) on the SmartRF05EB. Use SmartRF Flash Programmer to
do the actual programming.
Note that there is a way to force the boot loader not to start the firmware. Place the EB Mode
Selection switch in the CC2511JOYSTICK position and move the joystick in any direction
(other than the centre position). When the board is turned on, the firmware is not started and
the boot loader will have control of the board. The LED D6 will be blinking with a 1 second
2
Not included in this kit
There should not be any EM boards connected to the 05EB while
updating the firmware on the EB.