User manual

CY7C67200
Document #: 38-08014 Rev. *G Page 33 of 78
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
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’.
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
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