Cypress Semiconductor FX2LP Informations techniques Page 146

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EZ-USB FX2 Technical Reference Manual
Page 8-10 EZ-USB FX2 Technical Reference Manual v2.1
8.6.2 Registers That Control EP2, EP4, EP6, EP8
In order to achieve the high transfer bandwidths required by USB 2.0’s high-speed mode,
the FX2’s CPU should not participate in transfers to and from the “large” endpoints.
Instead, those endpoints are usually connected directly to external logic (see Chapter 9 and Chap-
ter 10 for details).
Some applications, however, may require the firmware to have at least some small amount of con-
trol over the large endpoints. For those applications, the FX2 provides the registers shown in
Table 8-5.
8.6.2.1 EP2468STAT
The Endpoint Full and Endpoint Empty status bits (described below, in Section 8.6.2.3) are repli-
cated here in order to allow faster access by the firmware.
8.6.2.2 EP2ISOINPKTS, EP4ISOINPKTS, EP6ISOINPKTS, EP8ISOINPKTS
For high-speed (480 Mbps) ISOCHRONOUS IN endpoints only, the INPPF1 and INPPF0 bits in
each of these registers determine the number of packets per microframe.
Table 8-5. Registers that control EP2,EP4,EP6 and EP8
Address Name Function
SFR 0xAA EP2468STAT EP2, 4, 6, 8 empty/full
0xE648 INPKTEND force end of IN packet
0xE640 EP2ISOINPKTS ISO IN packets per frame or microframe
0xE6A3 EP2CS npak, full, empty, stall
0xE690 EP2BCH byte count (H)
0xE691 EP2BCL byte count (L)
0xE641 EP4ISOINPKTS ISO IN packets per frame or microframe
0xE6A4 EP4CS npak, full, empty, stall
0xE694 EP4BCH byte count (H)
0xE695 EP4BCL byte count (L)
0xE642 EP6ISOINPKTS ISO IN packets per frame/microframe
0xE6A5
EP6CS
npak, full, empty, stall
0xE698
EP6BCH
byte count (H)
0xE699 EP6BCL byte count (L)
0xE643
EP8ISOINPKTS
ISO IN packets per frame/microframe
0xE6A6
EP8CS
npak, full, empty, stall
0xE69C
EP8BCH
byte count (H)
0xE69D EP8BCL byte count (L)
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