E.3.1. Boot Monitor configuration switches

The Boot Monitor application is typically loaded into the NOR flash memory and selected to run at power on. Follow the instructions in Loading Boot Monitor into NOR flash for details of loading the boot flash with the image from the Versatile CD.

Caution

The User Switches on the front panel of the ATX enclosure will not operate correctly if switch bank S4 on the PB-A8 baseboard is not in the default state of all switches OFF.

The setting of User Switch 1 determines how the Boot Monitor starts after a reset:

User Switch 1 OFF

A prompt is displayed enabling you to enter Boot Monitor commands.

User Switch 1 ON

The Boot Monitor executes a boot script that has been loaded into a Multimedia (MMC) or Secure Digital (SD) card. If a boot script is not present, the Boot Monitor prompt is displayed.

The boot script can execute any Boot Monitor commands. It typically selects and runs an application image that has been stored in either NOR flash memory or on the MMC or SD card. You can store one or more code images in flash memory and use the boot script to start an image at reset. Use the SET BOOTSCRIPT command to set the boot script file name from the Boot Monitor (see Boot Monitor command set).

Output and input of text from STDIO for both applications and Boot Monitor I/O depends on the setting of User Switches 2 and 3 as listed in Table E.1.

Table E.1. STDIO redirection

User Switch 2User Switch 3OutputInputDescription
OFFOFFUART0 or consoleUART0 or consoleSTDIO autodetects whether to use semihosting I/O or a UART. If a debugger is connected and semihosting is enabled, STDIO is redirected to the debugger console window. Otherwise, STDIO goes to UART0.
OFFONUART0UART0STDIO is redirected to UART0. This occurs even under semihosting.
ONOFFLCDKeyboardSTDIO is redirected to the LCD and keyboard. This occurs even under semihosting.
ONONLCDUART0STDIO output is redirected to the LCD and input is redirected to UART0. This occurs even under semihosting.

User Switches 2 and 3 do not affect file I/O operations performed under semihosting. Semihosting operation requires a debugger and a JTAG interface device. See Redirecting character output to hardware devices for more details on I/O.

Note

User Switches 4 to 8 are not used by the Boot Monitor and are always available for user applications.

If a different loader program is present at the boot location, the function of the entire User Switch bank is implementation dependent.

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