AM85C30(1992) 查看數據表（PDF） - Advanced Micro Devices

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AM85C30
(Rev.:1992)

Serial Communications Controller

Advanced Micro Devices 

SCC Application Notes

AMD

unsigned int fd;

int num_wr;

ptr = ptr + 3;

/*deletes device address and length of

file before writing onto the disk*/

num = num – 3;

printf(“What shall I name the received file?”);

var_nam = scanf(“%s”, name);

fd = creat(name, BWRITE);

if(fd<0) abort(“\ncreat error occured\n”);

num_wr = write(fd, ptr, num);

printf(“Number of bytes written to file rec.dat =

%d\n”,num_wr);

close(fd);

}

/*THIS ROUTINE INITIALIZES THE DMA CONTROLLER FOR RECEIVE*/

dminit()

{

unsigned int lsb, temp, msb, latch, wrdh, wrd1, tmp1, start;

unsigned int bytn, byt, tmp2;

outportb(0x09, 0x01); /*clear all DMA requests on channel 1*/

outportb(0x0A, 0x05); /*mask channel 1 DMA request*/

outportb(0x0B, 0x45); /*mode register for single transfer mode,

read, auto init, address increment*/

lsb = adrr & 0xFF;

temp = adrr >> 0x08; /*rotate ptr 8 bits to get msb*/

msb = temp & 0xFF;

temp = temp >> 0x08; /*rotate 8 bits to get sector address*/

latch = temp & 0x0F;

outportb(0x81, latch);/*load sector address into DMA page

register*/

outportb(0x02, lsb); /*lower byte of starting address*/

outportb(0x02, msb); /*upper byte of starting address*/

start = adrr & 0xFFFF;

bytn = num;

wrd1 = bytn & 0xFF; /*lower order byte of wordcount*/

tmp1 = bytn >> 0x08; /*rotate wordcount 8 bits for masb*/

wrdh = tmp1 & 0xFF; /*upper byte of wordcount*/

outportb(0x03, wrd1); /*this is the lower byte of # of bytes

that fit within the first sector*/

outportb(0x03, wrdh); /*upper byte of wordcount*/

outportb(0x0A, 0x01); /*enable DMA*/

outportb(port, 0x00);

outportb(port, 0x00); /*reset transmit underrun latch*/

}

/*THIS ROUTINE POLLS BIT D7 IN RR1 TO DETECT AN END–OF–MES-

SAGE*/

end()

{

unsigned char temp, ef;

unsigned int count;

ef = 0;

temp = 0

inportb(port);

outportb(port, 0x00);

outportb(port, 0x30);

while(ef==0)

{

count = 0;

7–43

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