DM164130-1 Datasheet DM164130-1, DV164132 | P19-P21

F1 EVALUATION PLATFORM

USER’S GUIDE

 2010 Microchip Technology Inc. DS41401B-page 19

Chapter 4. Demo Code

4.1 INTRODUCTION

The F1 Evaluation Platform demos are located at www.microchip.com/F1Eval. The

following demos are available:

1. I

C™ Demo

2. LCD Demo

3. BLDC Demo

4. Combined Demo

This chapter provides an overview to the functions provided by these demos.

4.2 I

C™ DEMO

The I

C demo reads the current temperature from the on-board MCP9800 I

temperature sensor. The I

C driver is used to extract the data. The resulting value is

converted to a PWM duty cycle and used to control the brightness of the LED D4. LED

D1 toggles at approximately 10 ms.

4.3 LCD DEMO

The LCD demo adds button, potentiometer, Real-Time Clock (RTC) and LCD support

to the I

C demo. The 32.768 kHz crystal is activated to maintain the Real-Time Clock

and to drive the LCD peripheral. An input driver is supplied to manage the button and

potentiometer. A state machine now controls the major features of the demo so that the

time, temperature and potentiometer value can be displayed on the LCD.

4.4 BLDC DEMO

The BLDC demo controls a sensorless, brushless DC motor connected to the PIC16F1

BLDC Expansion board (DM164130-2). Other motors can also be driven by making

appropriate modifications to the motor control parameters in the source code.

Refer to application note AN1305, “Sensorless 3-Phase Brushless Motor Control with

the PIC16FXXX” for detailed information regarding BLDC motor control.

4.5 COMBINED DEMO

The combined demo combines all the software from all the previous demos to show the

power of the PIC16LF1937. In this demo, the BLDC motor is seamlessly controlled

while displaying the time, temperature, potentiometer position or motor RPM/10. All

drivers are reused from the previous demos. The RTCC is driven from the LCD

peripheral.

The combined demo is preprogrammed in the F1 Evaluation Platform.

F1 Evaluation Platform User’s Guide

DS41401B-page 20  2010 Microchip Technology Inc.

NOTES:

F1 EVALUATION PLATFORM

USER’S GUIDE

 2010 Microchip Technology Inc. DS41401B-page 21

Chapter 5. Hardware Libraries and Drivers

5.1 INTRODUCTION

All of the demo code uses a common set of libraries to provide I

C, 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 I

C™ DRIVER

The I

C driver allows I

C 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 I

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

polls the I

C handler within the MCP9800 driver.

5.3 MCP9800 DRIVER

The MCP9800 driver uses the I

C driver to get the current temperature. The

mcp9800_get_temp function is fully blocking, so once a request is queued, the driver

polls the I

C subsystem until the data is complete. If the I

C driver is operating without

interrupts, the mcp9800_get_temp function repeatedly calls the I2C_handler

function to process all the I

C events. If the I

C driver is operating with interrupts, the

mcp9800_get_temp function simply inserts an I2C_TRANSACTION_T into the I

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.

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