DS41401A datasheet(21/42 Pages) MICROCHIP

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F1 EVALUATION PLATFORM

USER’S GUIDE

DS41401A-page 21

Chapter 5. Hardware Libraries and Drivers

5.1

INTRODUCTION

All of the demo code uses a common set of libraries to provide I2C, real-time clock,

MCP9800 and LCD services. These libraries may be useful for other applications so

they are documented here. These drivers are located at www.microchip.com/F1Eval.

5.2

I2C™ DRIVER

The I2C driver allows I2C requests to be queued and then handled either by interrupts

or by polling. The driver is configured during compilation to support polling or interrupts.

The I2C and LCD demos configure the driver for interrupt mode. The Combined demo

polls the I2C handler within the MCP9800 driver.

5.3

MCP9800 DRIVER

The MCP9800 driver uses the I2C driver to get the current temperature. The

mcp9800_get_temp

function is fully blocking, so once a request is queued, the driver

polls the I2C subsystem until the data is complete. If the I2C driver is operating without

interrupts, the mcp9800_get_temp function repeatedly calls the I2C_handler

function to process all the I2C events. If the I2C driver is operating with interrupts, the

mcp9800_get_temp

function simply inserts an I2C_TRANSACTION_T into the I2C

transaction queue and waits for the transaction to complete.

5.4

RTCC DRIVER

A software RTCC is managed by the supplied RTCC driver. This driver implements the

time()

function required by the C compiler. Time is internally kept as seconds since

January 1, 1970. Standard C functions can be used to convert the time to the current

date. This driver has two modes. In the first mode, it expects to be called once per

second by the Timer1 interrupt. In the second mode, it expects to be called on every

LCD mode B frame. This allows the RTCC to keep accurate time even if Timer1 is being

used by some other function, such as the BLDC motor driver.

5.5

LCD DRIVER

The LCD driver contains the initialization code required for the LCD peripheral and the

mapping code required to control the 3.5-digit LCD supplied with this demo board. It is

a good starting point for the LCD driver your unique application will require.

DS41401A Datasheet(PDF) 21 Page - Microchip Technology