NXP Semiconductors LPC1768 - Get Device Status (Command: 0 Xfe, Data: Read 1 Byte); Get Error Code (Command: 0 Xff, Data: Read 1 Byte)

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User manual Rev. 3 — 19 December 2013 249 of 841
NXP Semiconductors
UM10360
Chapter 11: LPC176x/5x USB device controller
11.12.7 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 Table 245
.
Remark: To ensure correct operation, the DEV_STAT bit of USBDevIntSt must be cleared
before executing the Get Device Status command.
11.12.8 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.
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 245. Set Device Status command bit description
Bit Symbol Value Description Reset value