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VersaKit-30xx
Ground Points on the Development Board
The VersaKit-30xx development board provides a ground access point (S1) located above the H18 Header on the right
side of the PCB. This point can be used to connect measurement instruments to ground.
2.5
Tact Switches
The development board includes two tact switches:
SW1 – VRS51L3074 Reset Switch. This switch allows a manual reset of the VRS51L3074 device. The
o
VRS51L3074 reset is active low.
Note: During programming or in-circuit debugging of the VRS51L3074, do not press SW1. Doing so could
result in loss of synchronization between the Versa Ware JTAG software and VRS51L3074 debugger.
SW2 – VRS51L3074 Interrupt Switch. This switch allows users to manually send a low pulse to the device's
o
INT0 pin. A connection can be established from the SW2 to the VRS51L3074 INT1 pin by installing a 0Ω
resistor at position R28 and removing the 0Ω resistor from R27.
2.6
User LEDs
The development board includes a set of eight uncommitted, 3mm, green user LEDs. The anode of each LED is
connected to the board's VCCMCU supply line through a 680R current limiting resistor, while the cathode of each LED is
connected to the user LED's H13 header footprint.
2.7
Character LCD Module Header Footprint
The development board features a header footprint (LCD1) for easy installation of a character LCD module. When
installed, the character LCD module header footprint and the VRS51L3074 are configured as follows:
Table 2: Character LCD header footprint pin-out
LCD
LCD Data [7:4]
LCD Data [3:0]
LCD E
LCD RW
LCD RS
LCD VEE
Most character LCD modules require a 5V supply. The LCD supply is accessed through H14. If the LCD module operates
from 3.3V, a 0Ω resistor can be installed at position R31 to connect the LCD module supply and the devboard supply.
The LCD drive pin (VEE) is accessible through H9. The LCD driving voltage that must be applied on the VEE pin of the
LCD module depends on the LCD type and varies among different manufacturers. Please consult the datasheet of your
specific LCD module to establish the proper voltage. For your convenience, we have included an unpopulated 0805
resistor footprint between the H9 and the LCD VEE pin, as well as a 0805 capacitor footprint between the LCD VEE pin
and the development board ground.
The LCD module backlight pins are accessible via the H15 2x1 header footprint
_______________________________________________________________________________________________
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Connected to
P0 [7:4]
Not connected
P0.2
P0.1
P0.0
Accessible through H9
page 9 of 28
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