Exp2 PPI DotMatrix
Control of Dot Matrix and 7-Segment
MDA-8086 Kit – PPI Application
Birzeit University
Information Technology Faculty
Computer Systems Engineering Department
Abstract
This experiment aims at understanding and testing the dot matrix structure, and the principle of display using the 82C55 Programmable Peripheral Interface devices.
The MDA 8086 subsystem will be used to control the display of patterns, digits, and characters. The display elements are:
- An 8x8 LEDs dot matrix
- A single 7-segment display
1
PART I Technical Introduction
1.1 Dot‐ Matrix LED Display
The KMD D1288C is 1.26 inch height 3mm diameter and 8 × 8 dot matrix LED displays. The
KMD D1288C is dual emitting color type of red, green chips are contained in a dot with milky and white lens color.
Figure 1 LED Matrix Connected to the PPI Ports
2
The dot matrix terminals are controlled using all three ports on an 82C55 peripheral programmable interface. Ports A and B are used to drive the cathode of the LEDs, while
Port-C would drive the anodes terminals. Port-A drives the red LEDs while port-B drives the green LEDs. If the two LEDs with the same coordinates are enabled then the outcome will be an orange dot. Ports A and B select the rows while Port-C select the columns as shown below:
Figure 2 LED Matrix
3
PART II Pre-Lab
(This part should be handed on to the teaching assistant in your Lab)
Study the schematics shown below (Figure 3) for the interface between the 82C55 PPI and the LED Dot Matrix (DOT1). Answer the following questions based on the details mentioned in the Practical Introduction and the schematics, as well as your review of the
82C55 datasheet:
1.
2.
3.
4.
What are the modes of operation the 82C55 ports A, B, and C?
What happens if all the PPI ports receive a byte of 0xFF from CPU?
What happens if Port-A receives a byte of 0x00 while Port-C receives a byte of 0xFF?
Referring to the schematics below, how can you disable the 82C55 PPI by a simple hardware change? Note: P6 is a
MDA-8086 Kit – PPI Application
Birzeit University
Information Technology Faculty
Computer Systems Engineering Department
Abstract
This experiment aims at understanding and testing the dot matrix structure, and the principle of display using the 82C55 Programmable Peripheral Interface devices.
The MDA 8086 subsystem will be used to control the display of patterns, digits, and characters. The display elements are:
- An 8x8 LEDs dot matrix
- A single 7-segment display
1
PART I Technical Introduction
1.1 Dot‐ Matrix LED Display
The KMD D1288C is 1.26 inch height 3mm diameter and 8 × 8 dot matrix LED displays. The
KMD D1288C is dual emitting color type of red, green chips are contained in a dot with milky and white lens color.
Figure 1 LED Matrix Connected to the PPI Ports
2
The dot matrix terminals are controlled using all three ports on an 82C55 peripheral programmable interface. Ports A and B are used to drive the cathode of the LEDs, while
Port-C would drive the anodes terminals. Port-A drives the red LEDs while port-B drives the green LEDs. If the two LEDs with the same coordinates are enabled then the outcome will be an orange dot. Ports A and B select the rows while Port-C select the columns as shown below:
Figure 2 LED Matrix
3
PART II Pre-Lab
(This part should be handed on to the teaching assistant in your Lab)
Study the schematics shown below (Figure 3) for the interface between the 82C55 PPI and the LED Dot Matrix (DOT1). Answer the following questions based on the details mentioned in the Practical Introduction and the schematics, as well as your review of the
82C55 datasheet:
1.
2.
3.
4.
What are the modes of operation the 82C55 ports A, B, and C?
What happens if all the PPI ports receive a byte of 0xFF from CPU?
What happens if Port-A receives a byte of 0x00 while Port-C receives a byte of 0xFF?
Referring to the schematics below, how can you disable the 82C55 PPI by a simple hardware change? Note: P6 is a
Bibliography: Tech., MEDAS. 2008. MDA 8086 Kit User Manual. Korea : s.n., 2008. 11