Cypress CY4672 manual Configuration Options, Battery Module

Mouse

When z-wheel motion is detected, the mouse module is notified for collection and reporting of the data; see Mouse Module on page 42.

3.3.5.7Battery Module

The battery monitor circuit is implemented using the Low Voltage Interrupt (LVI) on the LP radio. Fol- lowing is an explanation of the process to measure the battery voltage.

The process first sets the LVI threshold to 1.8V and then checks for an LVI interrupt. If the interrupt does not occur then it repeatedly sets the LVI TH and PMU OUTV with the following combination and checks the status.

Table 3-2. LVI TH and PMU OUTV Combinations

LVI TH	PMU OUTV	VOLTAGE IF INTERRUPT OCCURS
1.8V	2.7V	< 1.8V
2.0V	2.7V	< 2.0V
2.2V	2.7V	< 2.2V
PMU OUTV	2.7V	< 2.7V

It then returns a battery level between 1 and 10: 1 being below 1.8V and 10 being above 2.7 volts.

3.3.6Configuration Options

All configuration options for the application can be found in the config.h file, and some of them are defined in the Project > Setting > Compiler > Macro defines. Each option is explained below and can be changed to values that meet the developer’s needs.

3.3.6.1MOUSE_REPORT_IN_MS

This configuration value sets the shortest period at which the firmware honors events from the mouse hardware to transmit using the radio. The default value is approximately 10 milliseconds. Set- ting this value to something smaller than the USB poll period of 8 milliseconds generates excessive radio retries from the mouse and is not recommended. Larger values improve battery life, but may affect usability of the mouse. See the Timer Module on page 41 for a description of timing accuracy. This valued is defined in milliseconds.

3.3.6.2MOUSE_ACTIVE_MS

This value sets how long the timer module runs generating poll interrupts for the z-wheel and but- tons. This time affects power consumption of the mouse. Once this time expires, the buttons and z- wheel go into a power down state, improving battery life. In power down state, z-wheel movement exhibits latency. See the Buttons Module and Wheel Module on page 44 for descriptions of power down states and operation. This value is defined in milliseconds.

3.3.6.3MOUSE_DISCONNECTED_POLL_MS

Sets the rate at which the battery voltage is monitored while in the disconnected state. This ensures that if the batteries go below the minimum battery voltage of 1.8 V, the radio and optical sensor are prevented from turning on.

3.3.6.4MOUSE_TX_TIMEOUT_MS

The transmit loop in the mouse attempts to guarantee delivery of mouse events. This loop eventually times out if it does not receive a response from the bridge. This value sets that time-out time. The default value is 2000. This value is defined in milliseconds.

CY4672 Reference Design Guide, Document # 001-16968 Revision ** 45

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