Nxp Semiconductors UM10237 ユーザーズマニュアル
UM10237_2
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 02 — 19 December 2008
367 of 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.
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
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.
specification.
0100
Error in Token CRC.
0101
Error in Data CRC.
0110
Time Out Error.
0111
Babble.
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
Wrong Toggle Bit in Data PID, ignored data.
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.
The value read from a reserved bit is not defined.
NA
Table 353. Read 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.
specification.
0
2
DCRC
Data 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