Cypress CY4672 manual Firmware Architecture, Hardware Considerations, 1 ROM/RAM Usage

Mouse

test mode that is compatible with the Cypress Manufacturing Test Kit, use a shorting block and short together pins 4 and 5 before power is applied.

3.2.4Hardware Considerations

The mouse design uses the SS12 schottky diode (D1) and CDH53100LC inductor (L3) for its boost circuitry. With these high efficiency components, preliminary characterization data shows a range of approximately 74-87% efficiency for the 1.8-2.7V VBAT voltage range at different temperatures (-10C to 80C). The mouse is a higher power consumption device compared to the keyboard. Extend- ing the battery life is one of the crucial design considerations in the mouse design. The trade off for a higher efficiency boost circuitry is the component costs and the board size (these components are slightly bigger in size compared to the ones used in the keyboard design). These components do not provide enough current capacity at the low end of the VBAT voltage range to handle the worst case optical sensor load and the PMU output voltage may droop under these conditions. The recommen- dation is to use an external DC/DC boost circuit for the optical system only.

3.3Firmware Architecture

There are two architectural views of the mouse. The first is a microcontroller configuration view. This architecture and configuration is best viewed in the PSoC Designer™ application when the project is loaded. The second view is a logical organization of the source code modules that make up the mouse application code and other support modules.

This section describes both architectures with emphasis on top level organization and overall mod- ule operation. More detailed description of variables and functions should be obtained by studying the source code.

3.3.1ROM/RAM Usage

The following table shows the ROM/RAM usage. The top part exhibits the total ROM/RAM usage for basic functions, which disables all the build options below. The bottom part exhibits the ROM/RAM usage for individual build options.

Table 3-1. ROM/RAM Usage

Basic Function

Total ROM (Bytes)	Total RAM (Bytes)
5334	70

Build Option	ROM Usage (Bytes)	RAM Usage (Bytes)
MOUSE_BATTERY_STATUS	255	2
MOUSE_TEST_MODE	537	0
MFG_TEST_CODE	530	0
MFG_TX_MODES	755	2

3.3.2PRoC LP Device Configuration

The PRoC LP Programmable Radio on Chip is configured using the Device Editor in PSoC Designer. The mouse uses 2 digital blocks to support two separate user modules. The first module is an SPI master for communicating with the optical sensor and the radio. The second module is a Pro- grammable Interval Timer configured to operate as a 12-bit timer. The following is a screen shot of

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

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