Cypress Semiconductor CY7C1399B Bedienungsanleitung PDF herunterladen (Seite 14)

AN57322

November 4, 2009 Document No. 001-57322 Rev. ** 14

GPIFADRH = SETUPDAT[3];

// set GPIFADR[8:0] to address passed down

in wValue

GPIFADRL = SETUPDAT[2];

len = ( (SETUPDAT[5] << 8) +

SETUPDAT[4] ); // get transfer length from

wIndex field

while (len)

// while the transfer length is non-zero,

{

if( GPIFTRIG & 0x80 )

// if GPIF interface IDLE

{

if( !( EP68FIFOFLGS &

0x01 ) ) // if EP6 FIFO is not

full

{

if(enum_high_speed)

// if the FX2 enumerated at high-speed

{

if ( len >

0x0200 ) // if the transfer length

is greater than 512 bytes,

{

GPIFTCB1 = 0x02; // set GPIF transaction

count to 512, since

//

GPIFADR can only access 512

SYNCDELAY; // locations at a time

GPIFTCB0

= 0x00;

SYNCDELAY;

Tcount =

0x0200;

}

else

{

GPIFTCB1 = MSB(len);

SYNCDELAY;

GPIFTCB0

= LSB(len);

SYNCDELAY;

Tcount =

len;

}

}

else

// if the FX2 enumerated at full-speed

{

if ( len > 0x0040 )

// if the transfer length is greater than

64 bytes,

{

GPIFTCB1 = 0x00; // set GPIF

transaction count to 64

SYNCDELAY;

GPIFTCB0

= 0x40;

SYNCDELAY;

Tcount =

0x0040;

}

else

{

GPIFTCB1 = MSB(len);

SYNCDELAY;

GPIFTCB0

= LSB(len);

SYNCDELAY;

Tcount =

len;

}

}

GPIFTRIG = GPIFTRIGRD |

GPIF_EP6; // launch GPIF FIFO READ

Transaction to EP6IN

SYNCDELAY;

while( !( GPIFTRIG &

0x80 ) ) // poll GPIFTRIG.7 GPIF Done bit

{

;

}

SYNCDELAY;

xFIFOBC_IN = ( ( EP6FIFOBCH

<< 8 ) + EP6FIFOBCL ); // get EP6FIFOBCH/L

value

if( ( xFIFOBC_IN > 0) && (

xFIFOBC_IN < 0x0200 ) ) // if pkt is short,

{

INPKTEND = 0x06;

// force a commit to the host

}

len = len - Tcount;

// decrement transfer length by Tcount

if(!(len % 0x0200))

// if the transfer length is not a modulus

of 512, no need to

{

// reset GPIFADR[8:0] to access next bank

of 512 bytes,

GPIFADRH = 0x00;

// handles full-speed case and high-speed

case

GPIFADRL = 0x00;

// reset GPIFADR[8:0] to access the next

bank at offset 0

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