MCBx51 User's GuideIntroduction Setup Board Setup Board Components Connecting the MCBx51 Configuring the MCBx51 DIP Switches Configuration Jumpers Monitor Modes Monitor Status Display Microcontroller Selection Theory of Operation 251 Devices 8051 Devices
The DIP switch settings (along with the Configuration Jumpers) configure the MCBx51 board. Descriptions of each DIP switch follow the illustration.
Uart_INT (Switch 1): Default ON
The Uart_INT switch selects whether or not the external 16550 UART generates an interrupt on the microcontroller.
This switch is useful when using interrupt-driven serial I/O with the external UART. You must set Uart_INT to ON, if you want to halt execution of a user program within µVision.
ext_Uart (Switch 2): Default ON
The ext_Uart switch determines whether or not the chip select signal for the external 16550 UART is generated.
SRC/D2 (Switch 3): Default ON
The SRC/D2 switch selects SOURCE or BINARY mode on the 251 CPU.
The SRC/D2 must be ON when using the Dallas 320/420/520 device to select the Monitor version, which supports the Dual DPTR registers of that CPU. Refer to CPU Selection for a complete description on CPU types and related Monitor versions.
The SRC/D2 must be OFF when using a 151 or 8051 device and when running the MCBx51 with a user application in EPROM.
PAGE (Switch 4): Default OFF
The PAGE switch selects whether or not the 251 or 151 Monitor operates in page mode or non-page mode.
The configuration jumpers must also be set to PAGE for page mode or NONP for non-page mode for the MCBx51 board to run correctly.
If you operate the MCBx51 with a user application in EPROM, you must set the PAGE switch OFF. However, you may still use the jumpers to select page or non-page mode.
Monitor (Switch 5): Default ON
The Monitor switch selects if the Monitor is used for debugging or if the MCBx51 operates with a user application EPROM at IC13.
If you operate the MCBx51 with a user application EPROM, you must set the DIP Switches 51/151 (6), PAGE (4) and SRC/D2 (3) to OFF.
51/151 (Switch 6): Default OFF
The 51/151 switch selects whether a 251 or a 151/8051 compatible microcontroller is installed in the IC1 socket.
MAP1 (Switch 7), MAP0 (Switch 8): Default OFF, OFF
The MAP1 and MAP0 switches select the memory map for the MCBx51. The memory map used depends on the Monitor DIP switch setting. The memory for both Monitor settings is shown in the following tables.
LED (Switch 9): Default ON
The LED switch selects whether or not Port 1 is connected to the 8 LEDs in the upper right portion of the board.
If the Monitor DIP switch is ON and LED is OFF, the Monitor does not modify the port 1 lines on power-up.
A17 (Switch 10): Default ON
The A17 switch selects whether the 251 CPU uses P1.7 as the A17 address line or as an I/O port line.
The Monitor EPROM, which is supplied on the MCBx51 board, is configured for 256KB memory. Refer to the 251 or 151 data sheets for more information. If you use the MCBx51 board with an 8051 compatible device, such as the Intel 151 or Dallas 320, the A17 DIP switch must be OFF.
of your data.