UM10237_2 © NXP B.V. 2008. All rights reserved.
User manual Rev. 02 — 19 December 2008 367 o f 792
NXP Semiconductors UM10237
Chapter 13: LPC24XX USB device controller
11.9 Read Error Status (Command: 0xFB, Data: read 1 byte)

This command reads the 8-bit Error register from the USB device. This register records

which error events have recently occurred in the SIE. If any of these bits are set, the

ERR_INT bit of USBDevIntSt is set. The error bits are cleared after reading this register.

Table 352. Get Error Code Register bit description
Bit Symbol Value Description Reset
value
3:0 EC Error Code. 0x0
0000 No Error.
0001 PID Encoding Error.
0010 Unknown PID.
0011 Unexpected Packet - any packet sequence violation from the
specification.
0100 Error in Token CRC.
0101 Error in Data CRC.
0110 Time Out Error.
0111 Bab ble .
1000 Error in End of Packet.
1001 Sent/Received NAK.
1010 Sent Stall.
1011 Buffer Overrun Error.
1100 Sent Empty Packet (ISO Endpoints only).
1101 Bitstuff Error.
1110 Error in Sync.
1111 Wr ong Tog gle B it in Data PID, igno red d ata.
4 EA - The Error Active bit will be reset once this register is read.
7:5 - Reserved, user software should not write ones to reserved bits.
The value read from a reserved bit is not defined. NA
Table 353. Rea d Error Status Register bit description
Bit Symbol Description Reset value
0 PID_ERR PID encoding error or Unknown PID or Token CRC. 0
1 UEPKT Unexpected Packet - any packet sequence violation from the
specification. 0
2 DCRC Da ta CRC error. 0
3 TIMEOUT Time out error. 0
4 EOP End of packet error. 0
5 B_OVRN Buffer Overrun. 0
6 BTSTF Bit stuff error. 0
7 TGL_ERR Wrong toggle bit in data PID, ignored data. 0