> 7 | Sample Application

> Figure 52 shows a typical example of how to integrate a TC65 module with a Java application. Usage of the various host interfaces depends on the desired features of the application.
> Audio interface 1 demonstrates the balanced connection of microphone and earpiece. This solution is particularly well suited for internal transducers. Audio interface 2 uses an unbalanced microphone and earpiece connection typically found in headset applications.
> The charging circuit is optimized for the charging stages (trickle charging and software controlled charging) as well as the battery and charger specifications described in Section 3.5.
> The PWR_IND line is an open collector that needs an external pull-up resistor which connects to the voltage supply VCC µC of the microcontroller. Low state of the open collector pulls the PWR_IND signal low and indicates that the TC65 module is active, high level notifies the Power-down mode.
> If the module is in Power-down mode avoid current flowing from any other source into the module circuit, for example reverse current from high state external control lines. Therefore, the controlling application must be designed to prevent reverse flow.
> If the I2C bus is active the two lines I2CCLK and I2DAT are locked for use as SPI lines. Vice versa, the activation of the SPI locks both lines for I2C. Settings for either interface are made by using the AT^SSPI command.
> The internal pull-up resistors (Rp) of the I2C interface can be connected to an external power supply or to the VEXT line of TC65. The advantage of using VEXT is that when the module enters the Power-down mode, the I2CI interface is shut down as well. If you prefer to connect the resistors to an external power supply, take care that the interface is shut down when the PWR_IND signal goes high in Power-down mode.
> The interfaces ASC0, ASC1 and USB have different functions depending on whether or not Java is running. Without Java, all of them are used as AT interfaces. When a Java application is started, ASC0 and ASC1 can be used for CommConnection or/and System.out, and the USB lines can be used for debugging or System.out.
> The EMC measures are best practice recommendations. In fact, an adequate EMC strategy for an individual application is very much determined by the overall layout and, especially, the position of components. For example, mounting the internal acoustic transducers directly on the PCB eliminates the need to use the ferrite beads shown in the sample schematic. However, when connecting cables to the module’s interfaces it is strongly recommended to add appropriate ferrite beads for reducing RF radiation.
> Disclaimer
> No warranty, either stated or implied, is provided on the sample schematic diagram shown in Figure 51 and the information detailed in this chapter. As functionality and compliance with national regulations depend to a great amount on the used electronic components and the individual application layout manufacturers are required to ensure adequate design and operating safeguards for their products using TC65 modules.
> Figure 51: TC65 sample application