Cypress CY7C67200 manual Device n Endpoint n Count Result Register R/W

CY7C67200

Device n Endpoint n Count Result Register [R/W]

•Device n Endpoint 0 Count Result Register [Device 1: 0x0208 Device 2: 0x0288]

•Device n Endpoint 1 Count Result Register [Device 1: 0x0218 Device 2: 0x0298]

•Device n Endpoint 2 Count Result Register [Device 1: 0x0228 Device 2: 0x02A8]

•Device n Endpoint 3 Count Result Register [Device 1: 0x0238 Device 2: 0x02B8]

•Device n Endpoint 4 Count Result Register [Device 1: 0x0248 Device 2: 0x02C8]

•Device n Endpoint 5 Count Result Register [Device 1: 0x0258 Device 2: 0x02D8]

•Device n Endpoint 6 Count Result Register [Device 1: 0x0268 Device 2: 0x02E8]

•Device n Endpoint 7 Count Result Register [Device 1: 0x0278 Device 2: 0x02F8]

Figure 34. Device n Endpoint n Count Result Register

Bit #	15	14	13	12		11	10	9	8
Field					Result...
Read/Write	R/W	R/W	R/W	R/W		R/W	R/W	R/W	R/W
Default	X	X	X	X		X	X	X	X

Bit #	7	6	5	4		3	2	1	0
Field					...Result
Read/Write	R/W	R/W	R/W	R/W		R/W	R/W	R/W	R/W
Default	X	X	X	X		X	X	X	X

Register Description

The Device n Endpoint n Count Result register contains the size difference in bytes between the Endpoint Count specified in the Device n Endpoint n Count register and the last packet received. If an overflow or underflow condition occurs, that is the received packet length differs from the value specified in the Device n Endpoint n Count register, the Length Exception Flag bit in the Device n Endpoint n Status register will be set. The value in this register is only considered when the Length Exception Flag bit is set and the Error Flag bit is not set; both bits are in the Device n Endpoint n Status register.

The Device n Endpoint n Count Result register is a memory based register that must be initialized to 0x0000 before USB Device operations are initiated. After initialization, this register must not be written to again.

Result (Bits [15:0])

The Result field contains the differences in bytes between the received packet and the value specified in the Device n Endpoint n Count register. If an overflow condition occurs, Result [15:10] is set to ‘111111’, a 2’s complement value indicating the additional byte count of the received packet. If an underflow condition occurs, Result [15:0] indicates the excess byte count (number of bytes not used).

Reserved

All reserved bits must be written as ‘0’.

Document #: 38-08014 Rev. *G Page 33 of 78

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