UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
236 of 362
NXP Semiconductors
UM10208
Chapter 17: LPC2800 USB Device
8.34 USB DMA Channel Status Registers (UDMA0Stat - 0x8004 0000,
UDMA1Stat - 0x8004 0040)
These read-only registers contain information similar to that in the global DMA Status
register, except that these registers include more detailed error status.
All zeroes in bits 23:16 and 1:0 indicate that any previous DMA transfer concluded
successfully. 10 in the State field indicates that the channel’s Control register was written
with 00 in the CHEN field, and no change in any of the other fields. If the channel’s Control
register is written with a non-zero value in the CHEN field and no change in any of the
other fields, the Suspend state changes back to Busy, and the suspended DMA transfer is
resumed. Writing any other register of the DMA channel, changes a Suspend or Error
state to Idle.
Table 263. USB DMA Channel Status Registers (UDMA0Stat - 0x8004 0000, UDMA1Stat -
0x8004 0040)
Bit
Symbol
Description
Reset
value
1:0
State
00: Idle: this channel is not involved in execution of a DMA transfer
01: Busy: this channel is involved in execution of a DMA transfer
10: Suspend: this channel was suspended during its DMA transfer
11: Error: an error occurred during this channel’s DMA transfer.
0
15:2
-
Reserved. The values read from reserved bits is not defined.
-
16
Write Error This bit is 1 if an error (e.g. bus error) occurred while writing data to the
destination.
0
17
Dest FC
Error
This bit is 1 if a Peripheral Transfer Error was activated on the
destination Flow Control Port at the moment the DMA channel was
enabled.
0
19:18 -
Reserved. The values read from reserved bits is not defined.
-
20
Read Error This bit is 1 if an error (e.g. bus error) occurred while reading data from
the source.
0
21
Source FC
Error
This bit is 1 if a Peripheral Transfer Error was activated on the source
Flow Control Port at the moment the DMA channel was enabled.
0
22
Update
Error
This bit is 1 if one of the registers for this DMA channel or one of its
Flow Control ports was written while this DMA channel was active.
0
23
Config
Error
This bit is 1 if one of the fields in this DMA channel’s Control Register
was programmed with an invalid value. This bit is set as soon as the
Control Register is written with a non-zero CHEN field and an invalid
value.
0
31:24 -
Reserved. The values read from reserved bits is not defined.
-