Iic Driver Sample Application - Freescale Semiconductor DSP56800E User Manual

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IIC Driver Sample Application

The IIC driver application is designed for Freescale EVMs and is intended to illustrate the usage

of this driver by a real example. For the IIC module, the sample application contains a "complete"

IIC interrupt handler code, implementing the state diagram described below in Figure 5-3. The

code can be reused in user applications as a general-purpose IIC communication driver.

The IIC sample application demonstrates both the Master and Slave capabilities of the IIC

peripheral module. You will need two MC56F8013DEMO boards connected together via the IIC

bus (3 wires needed: SCL, SDA and GROUND).

1. Most of the time, the IIC is in Slave mode and waits for being addressed by the Master

— a) If Master uses a WRITE transaction, the BIT_0 and BIT_1 of (each) data byte received are

tested and we toggle the YELLOW[GPIO_A1] and/or GREEN[GPIO_A2] LEDs if BIT_0/1 is

— b) If Master uses a READ transaction, we respond with a byte where BIT_0 and BIT_1 report

what LEDs (GPIO_A1 and GPIO_A2) are ON.

2. Using an GPIO interrupt, we monitor the board buttons. Any time the button is pressed, the

IIC is switched to Master mode and a message is sent to a remote slave. The BIT_0 and

BIT_1 bits are set in the message data byte if button #1 and/or #2 were pressed. Thanks to

(1a) the remote node should respond by toggling the YELLOW and/or GREEN LEDs.

3. Even if no button is pressed, the IIC is periodically (approx. once per second) switched to

a Master mode and the remote note is queried for what LEDs are currently turned-on (see

1b). The returned message is then used to turn the status YELLOW and GREEN LEDs on

or off (GPIO_A4 and GPIO_A5).

The IIC device must not address itself so it is required to define different

REMOTE_ADDRES and the local slave address (in graphical

configuration tool).

The Graphical Configuration Tool was used to configure CPU pins and

peripheral modules in this application. See the appconfig.h file listing for

more details.

The application can be found at e.g. sample_applications\MC56F8013DEMO\iic_demo directory

and consists of the application project iic_demo.mcp, source code for the application main.c and

configuration file appconfig.h.

FREESCALE SEMICONDUCTOR

Targeting 56F8xxx Platform

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