UM10237_2 © NXP B.V. 2008. All rights reserved.
User manual Rev. 02 — 19 December 2008 366 o f 792
NXP Semiconductors UM10237
Chapter 13: LPC24XX USB device controller
11.7 Get Device Status (Command: 0xFE, Data: read 1 byte)
The Get Device Status command returns the Device Status Register. Reading the device
status returns 1 byte of data. The bit field definition is same as the Set Device Status
Register as shown in Table13–351.
Remark: To ensure correct operation, the DEV_STAT bit of USBDevIntSt must be cleared
before executing the Get Device Status command.
11.8 Get Error Code (Command: 0xFF, Data: read 1 byte)
Different error conditions can arise inside the SIE. The Get Error Code command returns
the last error code that occurred. The 4 least significant bits form the error code.
3 SUS_CH Suspend (SUS) bit change indica tor. The SUS bit can toggle
because:
The device goes into the suspended state.
The device is disconnected.
The device receives resume signalling on its upstream port.
This bit is cleared when read.
0
0 SUS bit not changed.
1 SUS bit changed. At the same time a DEV_STAT interrupt is
generated.
4 RST Bus Reset bit. On a bus reset, the device will automatically go to
the default state. In the default state:
Device is unconfigured.
Will respond to address 0.
Control endpoint will be in the Stalled state.
All endpoints are unrealized except control endpoints EP0
and EP1.
Data toggling is reset for all endpoints.
All buffers are cleared.
There is no change to the endpoint interrupt status.
DEV_STAT interrupt is generated.
Note: Bus resets are ignored when the device is not connected
(CON=0).
0
0 This bit is cleared when read.
1 This bit is set when the device receives a bus reset. A DEV_STAT
interrupt is generated.
7:5 - Reserved, user software should not write ones to reserved bits.
The value read from a reserved bit is not defined. NA
Table 351. Set Device Status Register bit description
Bit Symbol Value Description Reset
value