NXP Semiconductors LPC24XX UM10237 - Manual (Page 352)

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User manual Rev. 04 — 26 August 2009 352 of 792
NXP Semiconductors
UM10237
Chapter 13: LPC24XX USB device controller
9.6.5 USB Control register (USBCtrl - 0xFFE0 C228)
This register controls the data transfer operation of the USB device. It selects the endpoint
buffer that is accessed by the USBRxData and USBTxData registers, and enables
reading and writing them. USBCtrl is a read/write register.
9.7 SIE command code registers
The SIE command code registers are used for communicating with the Serial Interface
Engine. See
Section 13–11 “Serial interface engine command description” for more
information.
9.7.1 USB Command Code register (USBCmdCode - 0xFFE0 C210)
This register is used for sending the command and write data to the SIE. The commands
written here are propagated to the SIE and executed there. After executing the command,
the register is empty, and the CCEMPTY bit of USBDevIntSt register is set. See
Section 13–11 for details. USBCmdCode is a write only register.
Table 324. USB Transmit Packet Length register (USBTxPLen - address 0xFFE0 C224) bit
description
Bit Symbol Value Description Reset
value
9:0 PKT_LNGTH - The remaining number of bytes to be written to the
selected endpoint buffer. This field is decremented by 4 by
hardware after each write to USBTxData. When this field
decrements to 0, the TxENDPKT bit will be set in
USBDevIntSt. 0x000
31:10 - - Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined. NA
Table 325. USB Control register (USBCtrl - address 0xFFE0 C228) bit description
Bit Symbol Value Description Reset
value
0 RD_EN Read mode control. Enables reading data from the OUT
endpoint buffer for the endpoint specified in the
LOG_ENDPOINT field using the USBRxData register.
This bit is cleared by hardware when the last word of
the current packet is read from USBRxData. 0
0 Read mode is disabled.
1 Read mode is enabled.
1 WR_EN Write mode control. Enables writing data to the IN
endpoint buffer for the endpoint specified in the
LOG_ENDPOINT field using the USBTxData register.
This bit is cleared by hardware when the number of
bytes in USBTxLen have been sent. 0
0 Write mode is disabled.
1 Write mode is enabled.
5:2 LOG_ENDPOINT - Logical Endpoint number. 0x0
31:6 - - Reserved, user software should not write ones to
reserved bits. The value read from a reserved bit is not
defined. NA