AN2131-DK001 Cypress Semiconductor Corp, AN2131-DK001 Datasheet - Page 119

• Manufacturer Part Number: AN2131-DK001
• Description: KIT EZ-USB DEVELOPMENT BOARD
• Manufacturer: Cypress Semiconductor Corp

Specifications of AN2131-DK001

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 428-1333

Bulk endpoint data is available in 64-byte buffers in EZ-USB RAM. In some cases it is
preferable to access bulk data as a FIFO register rather than as a RAM. The EZ-USB core
provides a special data pointer which automatically increments when data is transferred.
Using this Autopointer, the 8051 can access any contiguous block of internal EZ-USB
RAM as a FIFO.
The 8051 first loads AUTOPTRH and AUTOPTRL with a RAM address (for example the
address of a bulk endpoint buffer). Then, as the 8051 reads or writes data to the data reg-
ister AUTODATA, the address is supplied by AUTOPTRH/L, which automatically incre-
ments after every read or write to the AUTODATA register. The AUTOPTRH/L registers
may be written or read at anytime. These registers maintain the current pointer address, so
the 8051 can read them to determine where the next byte will be read or written.
Page 6-22
AUTOPTRH
AUTOPTRL
AUTODATA
6.16
A15
R/W
R/W
R/W
A7
D7
b7
b7
b7
x
x
x
The Autopointer
A14
R/W
R/W
R/W
A6
D6
b6
b6
b6
x
x
x
A13
R/W
R/W
R/W
A5
D5
b5
b5
b5
x
x
x
Figure 6-12. Autopointer Registers
Autopointer Address High
Autopointer Address Low
Autopointer Data
Chapter 6. EZ-USB CPU
A12
R/W
R/W
R/W
A4
D4
b4
b4
b4
x
x
x
A11
R/W
R/W
R/W
A3
D3
b3
b3
b3
x
x
x
A10
R/W
R/W
R/W
A2
D2
b2
b2
b2
x
x
x
R/W
R/W
R/W
A9
A1
D1
b1
b1
b1
x
x
x
EZ-USB TRM v1.9
R/W
R/W
R/W
A8
A0
D0
b0
b0
b0
x
x
x
7FE3
7FE4
7FE5