CC3000 Schematic Checklist

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Introduction

This article is a review of the connections external to TI's CC3000 Module. When designing your own system around TI's CC3000 module, we recommend stepping through the guidelines outlined below.

NoteNote: You can now check your design with the CC3000 Checklist. The checklist enables you to verify your design in a series of easy-to-follow steps. The link to the checklist is below

File:CC3000 Checklist.zip

Check your design with this tool

Schematic Resources

Reference design files such as schematics, PCB files and gerber files are available from the download page.
Please locate the files for either the evaluation module or the booster pack within that page.


Critical Connections

Power

  • Please be aware that there are two Power Supply Pins:
    1. VBAT_IN - Primary Power Supply to the module (2.7V - 3.6V) (limited to 3.6V max - see CC3000 errata)
    2. VIO_HOST - Power Supply from the Host (1.8V - 3.6V)
  • Host control is available from VBAT_SW_EN, can tie to GPIO from Host processor.
  • Verify that all grounds are connected.

RF / Antenna Design

  • Verify the impedance of the matching circuit between the antenna and reference board.
  • The chosen antenna should have an impedance of 50 ohms.
  • If you chose to connect an external RF connector (i.e. a U.FL connection) please use the in-line capacitor connections to individually select either the antenna or external connection. As an example, please see the reference schematic.
  • Note: If you are unable to order the ACX AT8010-EZR9HAA antenna in your geographic region, you may be able to find the same antenna listed under the Johanson part number 2500AT44M0400. You can find an e2e discussion on the topic HERE.



Peripheral Connections

Clocks

  • Slow and Fast clock sources are provided within module.
  • Ground the external 32.768 kHz clock output (EXT_32K) signal if not using.

SPI

  • Verify the 5 wire SPI connection between the Host processor and CC3000.
The SPI is based on the five-line, master/slave communication model as shown in the following figure:
CC3000 HOSTSPI.PNG

The lines are described as follows:

I/O Description
SPI_CLK(1) Clock (0 to 16 MHz) from host to slave
SPI_CS(2) nCS (active low) signal from host to slave
SPI_DIN Data from host to slave
SPI_IRQ(3) Interrupt from slave to host
SPI_DOUT Data from slave to host



  • (1)SPI_CLK provides a clock to the SPI interface on the CC3000 device.
  • (2)SPI_CS selects a CC3000 device, indicating that a master wants to communicate to the CC3000 device.
  • (3)SPI_IRQ is a dual-purpose slave to the master direction line: in SPI IDLE state while no data transfer is active, driving IRQ low indicates to the master that the CC3000 device has data to pass to it; driving IRQ low following nCS deassertion indicates that the CC3000 device is ready to receive data. All behaviors are explained in detail in the following sections.

I2C

  • Verify that both I2C Data and I2C Clock lines are routed back to the module for Functional Mode. Notice that this done on the reference design through the population of 0ohm resistors.

Debug

Enable Pins

  • Test Mode vs Functional Mode
  • TI Reference Design makes use of a jumper to switch between the two modes
  • For Test Mode:
  • WL_EN1 – Leave disconnected
  • WL_EN2 – Connect to Ground
  • For Functional Mode (normal operation)
  • WL_EN1 and WL_EN2 - Shorted together

RS232 Signals

  • These connections are left open on the Reference Design in order to allow for a serial connection to a PC running the CC3000 Radio Test Tool


BOM Considerations

Please follow the BOM as given by the reference design. The BOM is reproduced below:

Component Manufacturer Part Number
2.4 GHz Chip Antenna, 8.0x1.0 mm ACX AT8010-E2R9HAA
RF Coaxial u.FL Connector Hirose U.FL-R-SMT-1(10)
Inductors ACX 2.2nH : Hl1005-1C2N2SMT
Capacitors Walsin
Walsin
Murata
2.2pF (x1) : 0402N2R2C500LT
10pF (x2) : 0402N100J500LT
1uF (x2) : GRM155R60J105KE19D
Resistors Walsin 0R : WR04X000 PTL
  • Note: If you are unable to order the ACX AT8010-EZR9HAA antenna in your geographic region, you may be able to find the same antenna listed under the Johanson part number 2500AT44M0400. You can find an e2e discussion on the topic HERE.