Digilent Basys Board Rev.C User Manual
Digilent Hardware
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Table of contents
Document Outline
- Overview
- Functional Description
- Power Supply
- User I/O
- Mouse
- The mouse outputs a clock and data signal when it is moved; otherwise, these signals remain at logic ‘1’. Each time the mouse is moved, three 11-bit words are sent from the mouse to the host device. Each of the 11-bit words contains a ‘0’ start bit, followed by 8 bits of data (LSB first), followed by an odd parity bit, and terminated with a ‘1’ stop bit. Thus, each data transmission contains 33 bits, where bits 0, 11, and 22 are ‘0’ start bits, and bits 11, 21, and 33 are ‘1’ stop bits. The three 8-bit data fields contain movement data as shown below. Data is valid at the falling edge of the clock, and the clock period is 20 to 30KHz.