Introduction

This post guides you through the process of using the virtual serial communications port that is bachelor inside the In-Circuit Debug Interface (ICDI) on the Texas Instruments EC-TM4C123GXL LaunchPad board. Nosotros'll be using the serial port under Windows 7 and communicating with a generic terminal program in this example.

Installing the ICDI drivers

There are three Windows drivers that must exist installed before you can fully utilise the ICDI interface on the LaunchPad. If you lot haven't installed them already, y'all tin can download the drivers and read the installations instructions here.

Configuring the target processor's serial port

The ICDI virtual serial port is hardwired to the RX and TX pins of UART0 of the target TM4C123G processor on the LaunchPad. In general, the user must initialize and configure the UART as well as the GPIO pins for RX0 and TX0. The general steps required are:

  • Enable the clock to GPIO Port A
  • Configure the function of the RX and TX pins
  • Enable the clock to UART0
  • Disable UART0 itself
  • Configure the baud rate, word length, end chip, and parity
  • Enable UART0

The user's plan is so responsible for sending and receiving data through the UART as necessary. Remember that the data must exist encoded as ASCII characters if you want to view it on a terminal.

Configuring the virtual COM port

ICDI_DevsAndPrntrsClipThe Windows driver for the virtual COM port must be configured to be uniform with the configuration of the UART on the TM4C123G. Open the Devices and Printers control panel and double click on the icon for the ICDI interface.

ICDI_PropsClick on the Hardware tab. Observe that the ICDI device provides several different functions through the single USB connection. The DFU device is used to update the ICDI firmware and the JTAG/SWD interface is used for debugging the target software. The Stellaris Virtual Serial Port is the interface that acts as the virtual COM port. Note that, for the example shown in the effigy, the virtual series port appears equally COM14 to Windows software. Double-click on this line to configure the COM port itself.

ICDI_COM_Props

Select the Port Settings tab. The settings here must be consistent with the configuration of the UART in the TM4C123G target processor. The use of 8 data $.25 with no parity and 1 terminate bit (the "8N1" configuration) is very common, but pay detail attention to the Bits per 2d setting (also known as the baud charge per unit). You lot probably volition not accept implemented whatsoever flow control unless y'all are using a high baud rate and so the most mutual setting here is None . Notation that the ICDI virtual serial port can not support hardware flow command.

Configuring the terminal program

The final step is to run the last program that will brandish any information that the host calculator receives from the ICDI virtual serial port, and will allow information to be sent to the target processor through the series port. In that location are many such programs available. This document describes how the PuTTYtel final programme is used, only the process of using another program would exist similar.

PuTTY_Config1

When PuTTYtel is started you will run into the chief configuration dialog. First, click the radio button to specify that the terminal volition apply a Serial connexion. At present you can modify the entry for the Series line to be the aforementioned as the serial port used past the virtual port driver, which happened to exist COM14 in the figure shown. Change the Speed setting to be the same as $.25 per second setting of the virtual COM port and the baud rate setting of the target processor'southward UART.

Now click on the Serial entry at the very bottom of the Category: list on the left side.

PuTTY_Config2

The Serial line to connect to and Speed entries should already exist correct if you entered them at the previous dialog. If non, modify them here.

Make certain that the entries for

  • Data bits
  • Stop bits
  • Parity
  • Flow control

are identical to the settings yous used when configuring the virtual serial port earlier, which must in turn be identical to the configuration of the target microcontroller's UART.

Click the Open push and the actual concluding window volition appear. Data sent from the microcontroller volition appear in this window, and text typed in this window will be transmitted to the microcontroller.