8237 modes-microprocessor, Assembly Language

Assignment Help:

8237 modes :

Intel 8237 can be set to four different type of style of transfer:

1) Single - One transfer at a time,  it allow processor access to the bus between transfers.

2) Block - Transfer all data, it do not allow processor access to the bus (may cause problems with memory refresh).

3) Demand - it keep transferring as long as target keeps DRQ asserted.

4) Cascade - it allow a slave controller use of the DMAC (used for DRQ4).

 

(A) In addition, the DMA controller can be set to make continuous transfers

o   It known as auto-initialized DMA

o   normally DMA is known as "single-cycle"

 

(B) 8237 is clocked at 1/2 of ISA Bus (0.5 *BLCK)

o   up to 4.166MHz (8.33 Mhz ISA)

o   Maximum transfer rate: 4.166MB/s (16-bit DMA)

o   Maximum Programmed I/O transfer rate: 2.77 MB/s

 

(C) Size of transfer

o   Master can only produce word-sized transfers

o   Slave can produce byte-sized transfers

o   Minimum transfer size: 1 byte

o   Maximum transfer size: 64KB (8-bit),128KB (16-bit)

 


Related Discussions:- 8237 modes-microprocessor

8254 programmable timer-microprocessor, 8254 Programmable Timer A diagr...

8254 Programmable Timer A diagram of Intel's 8254 interval event/timer counter is given in Figure. The 8254 consists of 3 identical counting circuits, per of which has GATE and

Signal descriptions of 8086-microprocessor, Signal descriptions of 8086 : ...

Signal descriptions of 8086 : described below are common for the maximum andminimum mode bothdata lines AD15 -AD0: These are the time multiplexed andmemory I/O address. Addre

Program, Write a program to separate out positive and negative numbers from...

Write a program to separate out positive and negative numbers from a given series of 16-bit hexadecimal numbers.

Assignment, Please let me know if you can do an assignment in the next 12 h...

Please let me know if you can do an assignment in the next 12 hours

Iret-loop-unconditional branch instruction-microprocessor, IRET : Return f...

IRET : Return from ISR:- When an interrupt service routine is called, before transferring control to it, the IP, CS  register and flag registers are stored in the stack to ment

Program, assembly language program to find larges number in an array

assembly language program to find larges number in an array

Aad-arithmetic instruction-microprocessor, AAD: ASCII Adjust for Division ...

AAD: ASCII Adjust for Division though the names of these 2 instructions (AAM and AAD) seem to be same, there is many difference between their functions. The AAD instruction conver

Rics/cisc architecture-microprocessor, RICS/CISC Architecture An essent...

RICS/CISC Architecture An essential aspect of computer architecture is the design of the instruction set for the processor.  The instruction set selected for a specific compute

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd