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In the cycle stealing mode, the DMA controller obtains access to the system bus the same way as in burst mode, using BR (Bus Request) and BG signals, which are the two signals controlling the interface between the CPU and the DMA controller. However, in cycle stealing mode, after one unit of data transfer, the control of the system bus is ...
Burst mode is a generic electronics term referring to any situation in which a ... In the case of DMA, the DMA controller and the device are given exclusive ...
To solve this problem, burst mode (BM) transmission is adopted for upstream channel. The given ONU only transmits optical packet when it is allocated a time slot and it needs to transmit, and all the ONUs share the upstream channel in the time division multiple access (TDMA) mode. The phases of the BM optical packets received by the OLT are ...
DMA is the only formal and predictable method for external devices to access RAM. This term is less common in modern computer architecture (above 66-100 MHz), where the various external buses and controllers generally run at different rates, and CPU internal operations are no longer closely coupled to I/O bus operations.
Intel 8237A-5, used on the original IBM PC motherboard Pinout. Intel 8237 is a direct memory access (DMA) controller, a part of the MCS 85 microprocessor family. It enables data transfer between memory and the I/O with reduced load on the system's main processor by providing the memory with control signals and memory address information during the DMA transfer.
This DMA controller is controlled by the UART's DMA mode signals that were defined for the 16550. The DMA controller requires the CPU to set up each transaction and poll a status register after the transaction is started to determine if the transaction is done. Each DMA transaction can transfer between 1 and 128 bytes between a memory buffer ...
Thus by simply repeatedly triggering the DMA pins, the system would walk through the entire memory. The DMA controller also provides a special "load mode", which allows loading of memory while the CLEAR and WAIT inputs of the processor are active. This allows a program to be loaded without the need for a ROM-based bootstrap loader.
ROR allows the master to retain control over the bus until a Bus Clear (BCLR*) is asserted by another master that wishes to arbitrate for the bus. Thus a master that generates bursts of traffic can optimize its performance by arbitrating for the bus on only the first transfer of each burst. This decrease in transfer latency comes at the cost of ...