CSE 477 -- Video Imaged Spatial Positioning Project

Preliminary Design Package
    Introduction
    Project Design
    Project Requirements
       Operating Envirnoment
       Project Specifications
          VISPS External Inter
          Operating Params
          Intersystem Comm
    Parts List
    Design Analysis
    Test Plans
    Design Issues
    Technical References
    Powerpoint Presentation
    Word Format
    Group H Design Review
    Design Review (Word)

Final Design Report

Product Brochure

Final Project Report

PROJECT REQUIREMENTS

For VISPS, we have defined a number of project requirements. Below are the operating parameters for VISPS and the operating conditions of the internal parts. We will also discuss the communication protocols that we will use between the subsystems.

Operating Environment

System functionality requires operation in an area that is NOT well lit by the sun or any intense light source.

Project Specification

For the project specifications, we will first discuss the interface that VISPS will use. Afterwards, we will discuss the physical operating parameters of the internal parts of VISPS. Then we will discuss the communication protocols that occur internally.

VISPS External Interfaces

VISPS will transmit the spatial coordinates out using the RS-232 protocol. In the RS-232, two lines are required: a transmit line and a ground. Figure 9 shows the interface.

Figure 9 - VISPS interfaces

In VISPS, the RS-232 protocol will run with the configuration shown in Table 2.

Table 2 - RS-232 configuration values

Parameter	Value
Baud Rate	19,200 bps
Number of bits	8
Parity	None
Number of stop bits	1
Flow Control	None

When streaming the coordinates out, we will send the bytes the order shown in Figure 10.

Figure 10 - Order of bytes sent on RS-232 port by the Atmel 8051 Microcontroller

In the byte output, the start byte will be 255 (0xff in hex) because no coordinate will have the value of 255. Then the next three bytes are the X, Y, and Z coordinates.

The X and Y coordinates will be normalized to positive integers. When the data correlator finished finding the coordinates, the X and Y coordinates will range from -127 to 127. Before outputting the X and Y coordinates, the data correlator will normalize these coordinates so that -127 will be 0 and 127 will be 254. For the Z coordinate, the output will not be normalized but the max value will be 254. The primary reason is because the Z coordinate can never be negative. After normalizing X and Y and limiting the max value of Z, we can use the value 255 as the start byte as neither X, Y, nor Z will ever have this value.

We require the use of a start byte so that whoever is interfacing with VISPS will be able to determine when VISPS begins transmitting a set of coordinates.

Physical Operating Parameters of Internal Parts

In Table 3 through Table 6 are the operating parameters for the following parts: the Spectronix RC-2BW, the Xess XS40-010XL development board, and the Atmel AT98C55-33PC 8051 Microcontroller. These parts are used in the VISPS design.

Table 3 - Spectronix RC-2BW (VV5404) camera

Operating Parameter	Value
Operating Voltage	6.0-12.0V
Supply Current	< 75 mA
Image Format	CIF
Image Size	356 x 292 pixels
Pixel Size	12.0 x 11.0 mm
Sensor Signal/Noise Ratio	46dB
Minimum Illumination	0.1 lux
Scope of Vision	28 degrees
Chipset	VLSI Vision VV5404
Frame Rate	30 fps
Internal Clock	7.15 MHz
QCK	Fast QCK

Table 4 - Xess XS40-010XL (XS-40) operating parameters

Operating Parameter	Value
Operating Voltage	9.0 (center positive)
Supply Current	< 25 mA
Clock Speed	24 MHz
Gate Count	20,000

Table 5 - Atmel AT89C55-33PC 8051 Microcontroller

Operating Parameter	Value
Operating Voltage	9.0
Supply Current	< 300 mA
Clock Speed	20 MHz
Gate Count	20 Kbytes

Intersystem Communication Protocols

In VISPS, there are two internal communication channels. The first is between the RC-2BW cameras and the XS-40. In this communication channel, the cameras will be streaming digital images to the XS-40. The protocol that is used to configure the camera and to retrieve data from the camera is defined in VLSI Vision's VV5404 datasheet.

The second internal communication channel is between the XS-40 and the Atmel Microcontroller. The protocol that will be used is modeled after a four-way handshake protocol. The protocol requires two control lines for the handshake and a data bus width of 8 bits for the data. Figure 11 shows a diagram of the control lines and the data bus.

Figure 11 - Diagram of the communication lines between the XS-40 and the Atmel mC

Figure 11 - Diagram of the communication lines between the XS-40 and the Atmel Microcontroller

The four-way handshake protocol has steps:

XS-40 drives the READY line high when the data bus contains the right values.
When the Atmel mC sees that the READY line is high, the mC reads that data and drives the DONE line high after finished reading the data.
The XS-40 returns an acknowledgement by pulling the READY line low.
The Atmel mC completes the handshake by pulling the DONE signal low.

This four-way handshake will be used to transmit each of the six pieces of pixel-coordinate data. There are three pixel coordinates that are 16 bits each in size. To reset the data transmission the Atmel mC will drive the new_data line high.