Cypress Semiconductor FX2LP Información técnica descargar pdf (Pagina 328)

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EZ-USB FX2 Technical Reference Manual

Page 15-8 EZ-USB FX2 Technical Reference Manual v2.1

FX2 provides two identical autopointers. They are similar to the internal “DPTR” data pointers, but

with an additional feature: each can automatically increment after every memory access. Using

one or both of the autopointers, FX2 firmware can perform very fast block memory transfers.

The AUTOPTRSETUP register is configured as follows:

• Set APTRnINC=0 to freeze the address pointer, APTRnINC=1 to automatically increment

it for every read or write of an XAUTODATn register. This bit defaults to 1, enabling the

auto-increment feature.

• To enable the autopointer, set APTREN=1. Enabling the Autopointers has one side-effect:

Any code access (an instruction fetch, for instance) from addresses 0xE67B and 0xE67C

will return the AUTODATA values, rather than the code-memory values at these two

addresses. This introduces a two-byte “hole” in the code memory.

The firmware then writes a 16-bit address to AUTOPTRHn/Ln. Then, for every read or write of an

XAUTODATn register, the address pointer automatically increments (if APTRnINC=1).

EP24FIFOFLGS Endpoint(s) 2, 4 Slave FIFO

Status Flags

SFR 0xAB

b7 b6 b5 b4 b3 b2 b1 b0

0 EP4PF EP4EF EP4FF 0 EP2PF EP2EF EP2FF

R R R R R R R R

0 0 1 0 0 0 1 0

EP68FIFOFLGS Endpoint(s) 6, 8 Slave FIFO

Status Flags

SFR 0xAC

b7 b6 b5 b4 b3 b2 b1 b0

0 EP8PF EP8EF EP8FF 0 EP6PF EP6EF EP6FF

R R R R R R R R

0 1 1 0 0 1 1 0

AUTOPTRSETUP Autopointer(s) 1 & 2 Setup SFR 0xAF

b7 b6 b5 b4 b3 b2 b1 b0

0 0 0 0 0 APTR2INC APTR1INC APTREN

R/W R/W R/W R/W R/W R/W R/W R/W

0 0 0 0 0 1 1 0

1 2 ... 323 324 325 326 327 328 329 330 331 332 333 ... 459 460

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