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DMA stands for 4-channel Direct Memory Access. It is specially The following image shows the pin diagram of a DMA controller −. _pin. 3S. Da. Do,. Doack o. DOACK 1. Do,. Figure 1. Block Diagram. Figure 2. Pin Configuration. MO0€. HAO -. HLDA -. PAIORITY. AE SOLVEA. ME WW -. AEN -. ADSTE -. INTERNAL. Bus. MAAK. Figure 1. Block Diagram. Figure 2. Pin Configuration. 2-

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These are bi-directional tri-state signals connected to the system data bus.

Features of Microcontroller. Analogue electronics Interview Questions. These are the active-low DMA acknowledge lines, which updates the requesting peripheral about the status of their request by the CPU. It specifies the address of the first memory location to be accessed.

Select your Language English. In the master mode, the lines which are used to send higher byte of the generated address are sent to the latch. This signal is used to demultiplex higher byte address and data using external latch.

Pin Diagram of | Block Diagram of | Mode Set Register | Status Register

Each channel has two sixteen bit registers:. Microprocessor Interview Questions. After reset the device is in the idle cycle.

In the slave mode, diagrma is connected with a DRQ input line These are the active-low and high inactive DMA acknowledge lines, which updates the peripheral requesting device service about the status of their request by the CPU. Leave a Reply Cancel reply Your email address will not be published.

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A “MEDIA TO GET” ALL DATAS IN ELECTRICAL SCIENCE!!: PROGRAMMABLE DMA CONTROLLER – INTEL

These are bidirectional, data lines which are used to interface the system bus with the internal data bus of DMA controller. These lines can also act as strobe lines for the requesting devices. It can be programmed to work in two modes, either in fixed mode or rotating priority mode.

Digaram master mode, it is used to send higher byte address A 8 -A 15 on the data bus. These are the four least significant address lines.

Pin Diagram of Microcontroller. Report Attrition rate dips in corporate India: This active high signal enables the 8-bit latch containing the upper 8-address bits onto the system address bus. These are used to indicate peripheral devices that the DMA request is granted. These are the four least significant address lines. Most significant four bits allow four different options for the Pin Diagram of This signal helps to receive the hold request signal sent from the output device.

Survey Most Productive year for Staffing: The value loaded into the low pij 14 bits C 13 — C 0 of the terminal count register specifies the number of DMA cycles minus one before the terminal count TC diagrram is activated.

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When the fixed priority mode is selected, then DRQ 0 has the highest priority and DRQ 3 has the lowest priority among them. It is the hold acknowledgement signal which indicates the DMA controller that the bus has been granted to the requesting peripheral by the CPU when it is set to 1.

Microprocessor 8257 DMA Controller Microprocessor

The active high Hold Acknowledge from the CPU indicates that it has relinquished control of the diafram bus. During DMA cycles these lines are used to send the most significant bytes of the memory address from one of the.

It consists of mode set register and status register. These are active low tri-state signals.

Your email address will not be published. It is necessary to load valid memory address in the DMA address register before channel is enabled. In the master mode, these lines are used to send higher byte of the idagram address to the latch. It is designed by Intel to transfer data at the fastest rate. Conditional Statement in Assembly Language Program.