Texas Instruments CC2520, User Manual

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7.5 Joystick
The joystick detects five positions (centre, up, down, left, right) and one event (pushed). In
case of moving the joystick from its centre position or pushing it, 5 discrete signals can be
used to distinguish what happened. The discrete signals are only available to the
microcontroller on the EM. In addition, two aggregated signals can be used to detect a
joystick event. One signal, JOY_MOVE, is set high in case of any movement away from the
centre position, including pushing. The other signal, JOY_LEVEL, is a voltage level signal that
gives different values depending on the current position of the joystick.
Joystick position JOY_LEVEL (Volts)
Up 0.31
Down 1.16
Left 1.62
Right 1.81
Centre 2.12
Table 2 - Voltage on JOY_LEVEL for different joystick positions
Measured at T=25°C, Vdd=3.0V
7.6 LCD
The LCD on SmartRF05EB is a 3x16 character display from Hitech Displays (HMC16311).
Use the SPI bus and the additional control signals (LCD CS, LCD Mode and LCD Reset) to
control the LCD.
7.7 Buttons
There are five buttons on the evaluation board.
Button 1 and Button 2 are only connected to the EM, while the USB button is connected to the
USB Controller. There are no RC filters on the buttons.
The USB Reset button resets the USB controller. Note that the USB controller will in turn
reset the EM, so pushing the USB reset button also resets the controller on the EM.
The EM reset button will only result in resetting the controller on the EM (e.g. the
MSP430F2618 on the CCMSP EM).
7.8 LEDs
There are 6 LEDs on the board.
The four LEDs D1, D2, D3 and D4 can only be controlled via the EM.
LED D6 can be controlled by the USB controller.
The LOW BATT LED is turned on when the voltage from the batteries drops below
approximately 1.56V.
7.9 Serial Flash
SmartRF05EB has a M25PE10 flash device – a 1 Mbit (128 Kb × 8 bit) serial paged flash
memory from STMicroelectronics. It can be accessed over the SPI bus from the EM, but not
from the USB Controller, as the latter has not access to the flash chip select signal.