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SBC Hardware: Main | SBC Schematic/Parts List | Technical Details | All pages in PDF format
SBC In-System Programming: Information | VisISP-52 ISP Application
SBCMON Monitor/Operating System: Main Page | Manual
SBCMON-based Software: SBCMON Monitor | Keypad Demo | LCD Echo Demo | Hardware Clock | Software Clock
SBCMON-based PS/2 Software: PS/2 Comm Monitor | PS/2 Keyboard | PS/2 Mouse

Powering up SBCMON

When power is applied to the SBC loaded with SBCMON, the yellow LED (D6) will flash on and off three times. This serves two purposes:

  1. It confirms that the SBCMON program is loaded correctly on the SBC and that the SBC is executing the monitor. This is useful since if there doesn't seem to be any communication between the PC and SBCMON, the flashing yellow LED will confirm that SBCMON is, in fact, executing. If the yellow LED flashes when the SBC is powered-up but nothing appears in the PC terminal program, the problem is almost certainly something to do with communications—either the wrong type of cable or the PC's terminal configuration is incorrect.
  2. It provides a delay of approximately 600 milliseconds. This is useful because the Atmel AT89S8252 has a published errata which indicates that problems may occur if a program accesses the SPI pins (P1.5, P1.6, and P1.7) during the first 500 milliseconds following an ISP process. The 600ms delay eliminates any possibility that these pins will be manipulated within this period.

Once power has been applied and the yellow LED has flashed on and off three times, SBCMON will send the message:

    SBCMON v1.3.0 Initialized.
    (Detected 32k of XRAM at 8000h)

This informs the user that the SBC has powered-up or has been reset. It also indicates whether or not SBCMON found XRAM that can be used to load programs. The monitor then enters the main menu mode.

SBCMON Main Menu

When SBCMON is ready to receive a command from the user it will display the following message:

    SBC Ready>

At this point the user may enter any valid command. A command consists of a single letter and zero or more additional parameters. The command is executed when the user presses ENTER.

When commands include a parameter, the first parameter is always entered immediately after the command letter with no space between them. For example:

The previously executed instruction may be executed again by hitting the ESCAPE key alone on a line. Commands are case-sensitive. This means the 'X' command is not the same as 'x'. All commands are upper-case except for one (the lower-case "w" command).

The following table lists all the commands that may be executed in SBCMON. Click on the link for each command for detailed syntax and additional information.

SBCMON Library Routines

Programs which are run from within SBCMON by loading them with the "L" command and executing them with the "R" command may make calls to a number of library routines that are contained within SBCMON itself. Using these routines saves the developer from having to rewrite the routines and avoid using code memory for a routine that is already contained within SBCMON.

For example, a simple program to send the digits "45" to the serial port could be:

The program may define each routine that it uses with an EQU definition and subsequently make calls to that routine. Click on each routine below for the parameters that must be set or which are returned by each routine.