Intel PXA255 manual UDC Frame Number MSB Fnmsb, Isochronous Packet Error Endpoint 4 IPE4

USB Device Controller

Table 12-24. UFNHR Bit Definitions

0x 4060_0060 UFNHR USB Device Controller

Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7

reserved SIR

6	5		4		3		2	1	0
SIM		IPE14		IPE9		IPE4		3-Bit
							Frame
							Number
								MSB

Reset x x x x x x x x x x x x x x x x x x x x x x x x 0 1 0 0 0 0 0 0

Bits	Name	Description
31:8	—	reserved
7	SIR	SOF Interrupt Request (read/write 1 to clear)
		1 = SOF has been received.
		SOF interrupt mask
6	SIM	0 = SOF interrupt enabled.
		1 = SOF interrupt disabled.
5	IPE14	Isochronous Packet Error Endpoint 14 (read/write 1 to clear)
		1 = Status indicator that data in the endpoint FIFO is corrupted
4	IPE9	Isochronous Packet Error Endpoint 9 (read/write 1 to clear)
		1 = Status indicator that data in the endpoint FIFO is corrupted
3	IPE4	Isochronous Packet Error Endpoint 4 (read/write 1 to clear)
		1 = Status indicator that data in the endpoint FIFO is corrupted
2:0	FNMSB	Frame Number MSB.
		Most significant 3-bits of 11-bit frame number associated with last receive SOF.

12.6.13.1UDC Frame Number MSB (FNMSB)

The UFNHR[FNMSB] is the three most significant bits of the 11-bit frame number contained in the last received SOF packet. The remaining bits are located in the UFNLR. This information is used for isochronous transfers. These bits are updated every SOF.

12.6.13.2Isochronous Packet Error Endpoint 4 (IPE4)

The isochronous packet error for Endpoint 4 is set if Endpoint 4 is loaded with a data packet that is corrupted. This status bit is used in the interrupt generation of endpoint 4. To maintain synchronization, the software must monitor this bit when it services an SOF interrupt and reads the frame number. This bit is not set if the token packet is corrupted or if the sync or PID fields of the data packet are corrupted.

12.6.13.3Isochronous Packet Error Endpoint 9 (IPE9)

The isochronous packet error for Endpoint 9 is set if Endpoint 9 is loaded with a data packet that is corrupted. This status bit is used in the interrupt generation of endpoint 9. To maintain synchronization, software must monitor this bit when it services the SOF interrupt and reads the frame number. This bit is not set if the token packet is corrupted or if the sync or PID fields of the data packet are corrupted.

Intel® PXA255 Processor Developer’s Manual 12-43