Datasheet

ATA/ATAPI Interface Port
11−14
SLLS535E − March 2008TUSB6250
The complete 32-bit transfer byte count (TRNS_BCN[31:0]) is stored in the USB or the ATA/ATAPI transfer
byte-count registers 0−3.
The initial TRNS_BCN[31:0] is used to indicate the expected total transfer byte count for a command, which
is equal to the dCBWDataTransferLength defined by the Universal Serial Bus Mass Storage Class Bulk-Only
specification. After data is transferred through the USB or ATA/ATAPI interface, TRNS_BCN[31:0] is
decremented accordingly. If the command is finished normally, the final TRNS_BCN[31:0] should become 0.
For ATA PIO mode, the MCU should load TRNS_BCN[17:9] with the expected sector number.
TRNS_BCN[17:9] is then copied to SEC_CNT[8:0] as the sector count initial value.
76543210
TRNS_BCN7 TRNS_BCN6 TRNS_BCN5 TRNS_BCN4 TRNS_BCN3 TRNS_BCN2 TRNS_BCN1 TRNS_BCN0
R/W R/W R/W R/W R/W R/W R/W R/W
BIT
NAME RESET FUNCTION
0 TRNS_BCN[7:0] 00h Transfer byte-count[7:0] value
11.5.8 TRANSBCNT1: USB or ATA/ATAPI Transfer Byte-Count Register 1 (XDATA at
F0D7)
76 5 43210
TRNS_BCN15 TRNS_BCN14 TRNS_BCN13 TRNS_BCN12 TRNS_BCN11 TRNS_BCN10 TRNS_BCN9 TRNS_BCN8
R/W R/W R/W R/W R/W R/W R/W R/W
BIT
NAME RESET FUNCTION
0 TRNS_BCN[15:8] 00h Transfer byte-count[15:8] value
11.5.9 TRANSBCNT2: USB or ATA/ATAPI Transfer Byte-Count Register 2 (XDATA at
F0D8)
76 5 43210
TRNS_BCN23 TRNS_BCN22 TRNS_BCN21 TRNS_BCN20 TRNS_BCN19 TRNS_BCN18 TRNS_BCN17 TRNS_BCN16
R/W R/W R/W R/W R/W R/W R/W R/W
BIT
NAME RESET FUNCTION
0 TRNS_BCN[23:16] 00h Transfer byte-count[23:16] value
11.5.10 TRANSBCNT3: USB or ATA/ATAPI Transfer Byte-Count Register 3 (XDATA at
F0D9)
76 5 43210
TRNS_BCN31 TRNS_BCN30 TRNS_BCN29 TRNS_BCN28 TRNS_BCN27 TRNS_BCN26 TRNS_BCN25 TRNS_BCN24
R/W R/W R/W R/W R/W R/W R/W R/W
BIT
NAME RESET FUNCTION
0 TRNS_BCN[31:24] 00h Transfer byte-count[31:24] value