UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
221 of 362
NXP Semiconductors
UM10208
Chapter 17: LPC2800 USB Device
8.15 USB Endpoint Index Register (USBEIX - 0x8004 102C)
The contents of this read/write register determine which endpoint is selected for reads
from, and writes to, the 5 registers described hereafter, namely the Endpoint Type
Register, the Endpoint Control Register, the Endpoint MaxPacketSize Register, the Data
Count Register, and the Data Port Register. Each IN and OUT endpoint implements an
independent set of these registers, and there is a set for the Setup function of Endpoint 0.
8.16 USB Endpoint Type Register (USBEType - 0x8004 1008)
This register sets the endpoint type. It also enables the endpoint and configures the
double-buffering. The correct maximim packet size must be first be defined in the
MaxPacketSize register before the endpoint is enabled.
To access this register, the Endpoint Index register must be written first with the target
endpoint number.
Table 245. USB Endpoint Index Register (USBEIX - 0x8004 102C)
Bit
Symbol
Description
Master
Reset
value
Bus
Reset
value
0
DIR
If the SEL_EP0SET bit in this register is 0, a 1 in this bit
selects IN endpoint identified by the ENDPIDX field of this
register, for reading and writing the registers listed above.
A 0 selects the OUT endpoint.
0
0
4:1
ENDPIDX
If the SEL_EP0SET bit in this register is 0, the value in this
field selects the endpoint number for reading and writing the
registers listed above. The maximum value for this field is
0111.
0
0
5
SEL_EP0SET A 1 in this bit selects the Endpoint 0 Setup registers for
reading and writing the registers listed above, and should
be accompanied by zeroes in bits4:0. Write a 0 to this bit to
select any other endpoint’s registers.
1
0
31:6 -
Reserved, software should not write ones to reserved bits.
The values read from reserved bits is not defined.
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