3.5 How can custom ISO/IEC 15693 commands be sent and received?

While TRF7970A EVM Control GUI provides many of the standard commands in the 15693 tab, more control may be necessary.

Low-level control of ISO/IEC 15693 commands is possible using the TRF7970A EVM Control GUI (to download, see Section 1.4). For test purposes, this is possible using the Test tab with this tool.

This example explains how to send a custom command that turns on or off an LED on the RF430FRL152HEVM. To test this feature, the EVM must be loaded with the Default project available in the RF430FRL152H firmware. The Default project has support for a custom command ID of AAh. The function where this is defined is called userCustomCommand in the main.c file. For the red Alarm LED to work, configure the EVM to be USB powered and set S6 to Supply.

To send a custom command of AAh with data of 0x10, this string is used: 18 02 AA 07 10

18: TRF7970AEVM Host command (omit for other readers; not sent out over RF)

02: Flags - high speed mode selection (start of actual RF packet)

AA: The actual custom command

07: TI Manufacturer ID (needed by the RF stack)

01: Turn on the Alarm LED (0x00 to turn off)

Before entering anything into the Test tab, it is important to set initial settings. Using the 15693 tab, it is important to set the TRF7970AEVM to the proper settings. This must be done only once.

1. Make sure that the only flag that is selected in the Tag Flags options is High Data Rate.

2. Click Set Protocol.

3. Go to the Test tab.

To issue the actual command to activate the red LED, enter the custom command string that was detailed previously into the String to send text box as: 1802AA0710.

To turn the LED off, the last byte of the command should be 00. Therefore to turn the LED off, enter this string: 1802AA0700.

For further information on the host control protocol for the TRF79xx, see TRF79xx ISO 15693 host commands.

More information on custom commands is provided in the section on adding custom commands in the RF430FRL15xH firmware user's guide.