Discuss 8237 DMA controller in detail.
The 8237 DMA Controller : 8237 is a programmable DMA controller present in 40 pin package. 8237 has a 4 channels with channel capable of transferring 64kb. It must interface with two types of devices : the MPU and peripherals such as floppy disks. As mentioned earlier, the DMA plays two roles in a given system : It is an I/O to the microprocessor (slave mode) and it is a data transfer processor to peripherals such as floppy disks (master mode). Many of its signals that are input in the I/O mode become outputs in the processor mode. It also needs additional signals lines to communicate with the address 64 k data bytes and these signals must be generated externally by using latches and buffers. The 8237 is complex device. To maintain clarity, the following discussion is divided into five segments : DMA channels and interfacing. DMA signals, system interface programming, and DMA execution.
Block Diagram of 8237 : Figure shows the internal block diagram of 8237. It contains blocks of control logic and internal registers.
|The block diagram of 8237 DMA controller|
Control Logic : The 8237 A contains three blocks of control logic.
- Timing Control Block : It generates internal timing and external control signal for the 8237A.
- Program Command Control Block : It decodes various commands given to 8237A by the microprocessor before servicing a DMA request. It also decodes the 'Mode control word, which is used to select the type of DMA during the servicing.
- Priority Encoder Block : It resolves the priority between DMA channels requesting services simultaneously.
- Internal Registers : The 8237 contains 344 bits internal memory in the form of registers.
Great Article… I love to read your articles because your writing style is too good, its is very very helpful for all of us and I never get bored while reading your article because, they are becomes a more and more interesting from the starting lines until the end.Reply
Devops training in velachry
Devops training in OMR
Deops training in annanagar
Devops training in chennai
Devops training in marathahalli
Devops training in rajajinagar
Devops training in BTM Layout
salesforce training in btm
salesforce admin training in btm
salesforce developer training in btm
inplant training in chennai
inplant training in chennai
online python internship
online web design
online machine learning internship
online internet of things internship
online cloud computing internship
online penetration testing
internship in bangalore for cse students
internship for aerospace engineering students in india
core companies in coimbatore for ece internship
paid internship in pune for computer engineering students
automobile internship in chennai
internship in chennai for eee with stipend
internship for bca students
dotnet training in chennai
aeronautical engineering internship
inplant training for ece students
Post a Comment