Texas Instruments Chipcon CC2400DBK, User Manual

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SWRU048 Page 11 of 30
Pin
number Signal name in
schematic Pin usage CC2400
pin AVR pin
1
2
3 RESET Reset 29 (PC6/RESET)
4 SCLK CC2400 serial clock,
AVR ISP
32 (SCLK) 17 (PB5/SCK)
5 PC5 Green LED 28 (PC5/ADC5/SCL)
6 SO CC2400 SPI out, AVR
ISP 34 (SO) 16 (PB4/MISO)
7 PD4 Yellow LED 2 (PD4/XCK/T0)
8 SI CC2400 SPI in, AVR
ISP 33 (SI) 15 (PB3/MOSI/OC2)
9 ADC7 Temperature sensor 22 (ADC7)
10 GIO6 CC2400 GIO6 35 (GIO6) 23 (PC0/ADC0)
11 ADC6 Not used 19 (ADC6)
12 DCLK/FIFO CC2400 DCLK/FIFO 30
(DCLK/FIF
O) 32 (PD2/INT0)
13 CSn CC2400 chip select 31 (CSn) 14 (PB2/SS/OC1B)
14 DIO/PKT CC2400 DIO/PKT 29
(DIO/PKT)
1 (PD3/INT1)
15 3.3V 3.3V regulated supply
16 TX CC2400 TX 28 (TX) 25 (PC2/ADC2)
17 1.8V 1.8V regulated supply
18 RX CC2400 RX 27 (RX) 26 (PC3/ADC3)
19 GIO1 CC2400 GIO1 21 (GIO1) 24 (OC1/ADC1)
20 GND Ground
Table 3: P4 pinout
PCB layout
RF circuits operating at high frequencies are normally sensitive to the physical layout of the
PCB. Chipcon has carefully optimized the layout of the CC2400DB Demonstration Board and
we therefore recommend that our customer copy, at least the RF parts and the decoupling
around the CC2400 when making their own PCB designs.
The PCB is of a 4-layer type in order to provide a well-defined ground plane as well as
adequate routing space. The laminate used is standard FR-4 board material. The PCB is
1.0mm thick, with layer 1 on the topside, layers 2 and 3 are internal layers and layer 4 is on
the bottom side. Layers 1 and 4 are used for routing, while layer 2 is a ground plane and layer
3 is used for power routing. All areas in the RF section that are not utilized for routing are
filled with copper connected to ground to provide RF shielding. The ground planes on all
layers are stitched together with closely spaced vias.