Category: INTERFACING ICS

IC 1408 DAC Pin Diagram

IC 1408 DAC Pin Diagram: The IC 1408 DAC Pin Diagram is an 8 bit R/2R ladder type D/A converter compatible with TTL and CMOS logic. It is designed to use where the output current is linear product of an eight bit digital word. Fig. 14.108 shows the pin diagram and block diagram for IC […]

Interfacing of 8279 with 8085

Interfacing of 8279 with 8085 in I/O Mapped  I/O: Fig. 14.98 shows the Interfacing of 8279 with 8085 in I/O mapped I/O technique. Here RD and WR signals are activated when IO/M signal is high, indicating I/O bus cycle. Reset out signal from 8085 is connected to the Reset signal of the 8279. CLK input […]

Operating Modes of 8279

Operating Modes of 8279: The Operating Modes of 8279 provides 3 basic input modes : Scanned keyboard Scanned sensor matrix Strobed input Scanned Keyboard: In this mode, keyboard can be scaned in two ways : Encoded scan and decoded scan. Encoded scan : In the encoded scan, scan lines (SL2-SL0) are decoded externally to provide […]

Block Diagram of 8279

Block Diagram of 8279: Fig. 14.84 shows the block diagram of 8279. It consists of four main sections CPU interface and control section Scan section Keyboard section Display section 1.CPU Interface and Control Section: This section consists of data buffers, I/O control, control and timing registers, and timing and control logic. Data Buffers The data […]

Pin Diagram of 8279

Pin Diagram of 8279: Fig. 14.83 shows functional and pin diagram of 8279. It is a 40 pin device and looking at Fig. 14.83 (a) we can see that these pins are divided in four functional groups : CPU interface Key data Display data Scan CPU Interface Pins: As shown in Fig. 14.83 (a), it […]

8279 Programmable Keyboard Display Interface

8279 Programmable Keyboard Display Interface: The Intel 8279 is a general purpose programmable keyboard and display I/O interface device designed for use with Intel microprocessors. The Features of 8279 Programmable Keyboard Display Interface are 1. It provides a scanned interface to a 64-contact key matrix, with two more keys CONTROL and SHIFT. 2. It provides three […]