8237 modes-microprocessor, Assembly Language

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)

 

Posted Date: 10/11/2012 12:29:36 AM | Location : United States







Related Discussions:- 8237 modes-microprocessor, Assignment Help, Ask Question on 8237 modes-microprocessor, Get Answer, Expert's Help, 8237 modes-microprocessor Discussions

Write discussion on 8237 modes-microprocessor
Your posts are moderated
Related Questions
MyLocation SDWORD 14 TheTest        SDWORD 8     mov    eax,MyLocation     mov    ebx,TheTest     neg     eax,ebx     sub     eax,ebx Show exactly what lives in eax after executi

Write a nonrecursive version of the Factorial procedure (Section 8.3.2) that uses a loop. (A VideoNote for this exercise is posted on the Web site.) Write a short program that inte

I need a division subroutine. Asks for two inputs, then displays the inputs and shows the answer with a remainder. Mine isnt displaying the inputs correctly.

Arithmetic Instruction :               These instructions are usually perform the arithmetic operations, like subtraction ,multiplication, addition, and division along with th

Write an application that does the following: (1) fill an array with 50 random integers; (2) loop through the array, displaying each value, and count the number of negative values;

Can any one assist me with this program. I am not efficient with assembly language and I need assistance badly. I am not asking anyone to do my work I just need help step by step

which uses BIOS interrupt INT 21 to read current system time and displays it on the top-left corner of screen.

Explain the architecture of the file transfer protocol ftp in terms of clients, servers, sockets

Write a MC68HC12 assembly language program to average ten 16-bit values that are stored starting at address $1100. Place the two-byte result at $1110. Use indexed addressing. Us

Program : A program to move a string of the data words from offset 2000H to offset 3000H the length of the string is OFH. Solution : For writing this program, we will use