AN2131-DK001 Cypress Semiconductor Corp, AN2131-DK001 Datasheet - Page 236

• 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

Bit 7:
The ISOSEND0 bit is used when the EZ-USB chip receives an isochronous IN token
while the IN FIFO is empty. If ISOSEND0=0 (the default value), the EZ-USB core does
not respond to the IN token. If ISOSEND0=1, the EZ-USB core sends a zero-length data
packet in response to the IN token. Which action to take depends on the overall system
design. The ISOSEND0 bit applies to all of the isochronous IN endpoints, IN8BUF
through IN15BUF.
Bit 5-3:
Set the endpoint pairing bits (PRxOUT) to “1” to enable double-buffering of the bulk
OUT endpoint buffers. With double buffering enabled, the 8051 can operate on one buffer
while another is being transferred over USB. The endpoint busy and interrupt request bits
function identically, so the 8051 code requires no code modification to support double
buffering.
When an endpoint is paired, the 8051 uses only the even-numbered endpoint of the pair.
The 8051 should not use the paired odd endpoint’s IRQ, IEN, VALID bits or the buffer
associated with the odd numbered endpoint.
Bit 2-0:
Set the endpoint pairing bits (PRxIN) to “1” to enable double-buffering of the bulk IN
endpoint buffers. With double buffering enabled, the 8051 can operate on one buffer
while another is being transferred over USB.
When an endpoint is paired, the 8051 should access only the even-numbered endpoint of
the pair. The 8051 should not use the IRQ, IEN, VALID bits or the buffer associated with
the odd numbered endpoint.
EZ-USB TRM v1.9
USBPAIR
ISOSEND0
R/W
b7
0
ISOSEND0
PRnOUT
PRnIN
R/W
b6
-
x
PR6OUT
Figure 12-35. USB Endpoint Pairing Register
R/W
b5
0
Isochronous Send Zero Length Data Packet
Pair Bulk OUT Endpoints
Pair Bulk IN Endpoints
USB Endpoint Pairing
Chapter 12. EZ-USB Registers
PR4OUT
R/W
b4
0
PR2OUT
R/W
b3
0
PR6IN
R/W
b2
0
PR4IN
R/W
b1
0
Page 12-43
PR2IN
R/W
7FDD
b0
0