Texas Instruments Chipcon CC2400DBK, User Manual, Page: 8 / 31

SWRU048 Page 8 of 30
RS-232 interface
A serial port is included on the CC2400DB. This port is used when software is programmed
into the AVR MCU using the boot loader, and is also used by several of the example
programs. The port includes support for RTS/CTS-type hardware flow control (handshaking).
Important:
It is important to be aware that maximum data rate for the Atmega8 RS-232 interface on
CC2400DB is 38.4 Kbps due to the use of the internal RC oscillator. Please see the Atmega8
datasheet for a baud rate error overview with the respect to a selected oscillator frequency.
Microcontroller and user interface
The microcontroller used is an AVR Atmega8L from Atmel. This controller has 8 KB of Flash
program memory, 1 KB of SRAM data memory and 512 bytes of non-volatile EEPROM data
memory. The controller runs on its internal oscillator, and is interfaced to the CC2400 via its
built-in SPI interface as well as some general I/O pins.
The MCU is also connected to three LEDs, a joystick and an extra button for user interface
purposes. The different examples use these peripherals differently. An analog temperature
sensor is also included.
An ISP connector is provided for programming the AVR without using the serial port. In this
case an Atmel AVR programmer should be connected to this connector.
All of the I/O pins are connected to footprints for 2 x 10 pin-row connectors. These connectors
are compatible with Agilent logic analyzer probes, and can be used either for testing or for
prototyping. For instance, it is possible to add a daughter board with additional circuitry using
these connectors.
AVR Pin
Number AVR pin name Pin usage I/O connector
1 PD3/INT1 CC2400 DIO/DKT P4 pin 14
2 PD4/XCK/T0 Yellow LED P4 pin 7
7 PB6/XTAL1/TOSC
1
Joystick up P3 pin 9
8 PB7/XTAL2/TOSC
2
Joystick right P3 pin 7
9 PD5/T1 Joystick down P3 pin 6
10 PD6/AIN0 Joystick left P3 pin 3
11 PD7/AIN1 Joystick center push P3 pin 5
12 PB0/ICP RS-232 handshaking RTS, push
button P3 pin 13
13 PB1/OC1A RS-232 handshaking CTS, Red LED P3 pin 17
14 PB2/SS/OC1B CC2400 chip select P4 pin 13
15 PB3/MOSI/OC2 CC2400 SI, AVR ISP P4 pin 8
16 PB4/MISO CC2400 SO, AVR ISP P4 pin 6
17 PB5/SCK CC2400 SCK, AVR ISP P4 pin 4
19 ADC6 Not used P4 pin 11
22 ADC7 Temperature sensor P4 pin 9
23 PC0/ADC0 CC2400 GIO6 P4 pin 10