Usb Receive Data Register (Usbrxdata - 0Xe009 0018); Usb Receive Packet Length Register (Usbrxplen - 0Xe009 0020); Usb Transmit Data Register (Usbtxdata - 0Xe009 001C); Usb Transmit Packet Length Register (Usbtxplen - 0Xe009 0024) - Philips LPC214 Series User Manual

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Volume 1

14.8.3 USB Receive Data register (USBRxData - 0xE009 0018)

For an OUT transaction, CPU reads the endpoint data from this register. Data from the
endpoint RAM is fetched and filled in this register. There is no interrupt when the register
is full. The USBRxData is a read only register.
Table 199: USB Receive Data register (USBRxData - address 0xE009 0018) bit description
Bit
31:0

14.8.4 USB Receive Packet Length register (USBRxPLen - 0xE009 0020)

This register gives the number of bytes remaining in the EP_RAM for the current packet
being transferred and whether the packet is valid or not. This register will get updated at
every word that gets transferred to the system. Software can use this register to get the
number of bytes to be transferred. When the number of bytes reaches zero, an end of
packet interrupt is generated. The USBRxPLen is a read only register.
Table 200: USB Receive Packet Length register (USBRxPlen - address 0xE009 0020) bit
Bit
9:0
10
11
31:12 -

14.8.5 USB Transmit Data register (USBTxData - 0xE009 001C)

For an IN transaction the CPU writes the data into this register. This data will be
transferred into the EP_RAM before the next writing occurs. There is no interrupt when the
register is empty. The USBTxData is a write only register.
Table 201: USB Transmit Data register (USBTxData - address 0xE009 001C) bit description
Bit
31:0

14.8.6 USB Transmit Packet Length register (USBTxPLen - 0xE009 0024)

The software should first write the packet length (≤ Maximum Packet Size) in the Transmit
Packet Length register followed by the data write(s) to the Transmit Data register. This
register counts the number of bytes transferred from the CPU to the EP_RAM. The
9397 750 XXXXX
User manual
Symbol Description
ReceiveData Data received.
description
Symbol Value Description
PKT_LNGTH - The remaining amount of data in bytes still to be read from
the RAM.
DV Non-isochronous end point will not raise an interrupt when
an erroneous data packet is received. But invalid data
packet can be produced with bus reset. For isochronous
endpoint, data transfer will happen even if an erroneous
packet is received. In this case DV bit will not be set for the
packet.
0 Data is invalid.
1 Data is valid.
PKT_RDY - Packet length field in the register is valid and packet is ready
for reading.
- Reserved, user software should not write ones to reserved
bits. The value read from a reserved bit is not defined.
Symbol Description
TransmitData Transmit Data.
Rev. 01 — 15 August 2005
UM10139
Chapter 14: USB Device Controller
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
Reset value
0x0000 0000
Reset
value
0
0
0
NA
Reset value
0x0000 0000
211