Read Current Frame Number (Command: 0Xf5, 14.11 Data: Read 1 Or 2 Bytes); Read Test Register (Command: 0Xfd, Data: Read 2 Bytes); Set Device Status (Command: 0Xfe, Data: Write 1 Byte) - Philips LPC214 Series User Manual

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14.9.4 Read Current Frame Number (Command: 0xF5, Data: read 1 or 2
bytes)
Returns the frame number of the last successfully received SOF. The frame number is
eleven bits wide. The frame number returns least significant byte first. In case the user is
only interested in the lower 8 bits of the frame number, only the first byte needs to be read.

14.9.5 Read Test Register (Command: 0xFD, Data: read 2 bytes)

The test register is 16 bits wide. It returns the value of 0xA50F, if the USB clocks (48 Mhz
and hclk) are fine.

14.9.6 Set Device Status (Command: 0xFE, Data: write 1 byte)

The Set Device Status command sets bits in the Device Status Register.
Table 229: Set Device Status Register bit description
Bit Symbol
0
1
2
9397 750 XXXXX
User manual
•
In case no SOF was received by the device at the beginning of a frame, the frame
number returned is that of the last successfully received SOF.
•
In case the SOF frame number contained a CRC error, the frame number returned will
be the corrupted frame number as received by the device.
Value Description
CON The Connect bit indicates the current connect status of the
device. It controls the SoftConnect_N output pin, used for
SoftConnect. Reading the connect bit returns the current connect
status.
0 Writing a 0 will make SoftConnect_N inactive.
1 Writing a 1 will make SoftConnect_N active.
CON_CH Connect Change.
0 This bit is reset when read.
1 This bit is set when the device's pull-up resistor is disconnected
because VBus disappeared. DEV_STAT interrupt is generated
when this bit is 1.
SUS Suspend: The Suspend bit represents the current suspend state.
When the device is suspended (SUS = 1) and the CPU writes a 0
into it, the device will generate a remote wakeup. This will only
happen when the device is connected (CON = 1). When the
device is not connected or not suspended, writing a 0 has no
effect. Writing a 1 into this register has never an effect.
0 This bit is reset to 0 on any activity.
1 This bit is set to 1 when the device hasn't seen any activity on its
upstream port for more than 3 ms.
Rev. 01 — 15 August 2005
UM10139
Chapter 14: USB Device Controller
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
Reset
value
0
0
0
225