User manual

CY7C67200
Document #: 38-08014 Rev. *G Page 22 of 78
Host n Endpoint Status Register [R]
• Host 1 Endpoint Status Register 0xC086
• Host 2 Endpoint Status Register 0xC0A6
Figure 21. Host n Endpoint Status Register
Register Description
The Host n Endpoint Status register is a read-only register that
provides status for the last USB transaction.
Overflow Flag (Bit 11)
The Overflow Flag bit indicates that the received data in the
last data transaction exceeded the maximum length specified
in the Host n Count Register. The Overflow Flag should be
checked in response to a Length Exception signified by the
Length Exception Flag set to ‘1’.
1: Overflow condition occurred
0: Overflow condition did not occur
Underflow Flag (Bit 10)
The Underflow Flag bit indicates that the received data in the
last data transaction was less then the maximum length
specified in the Host n Count register. The Underflow Flag
should be checked in response to a Length Exception signified
by the Length Exception Flag set to ‘1’.
1: Underflow condition occurred
0: Underflow condition did not occur
Stall Flag (Bit 7)
The Stall Flag bit indicates that the peripheral device replied
with a Stall in the last transaction.
1: Device returned Stall
0: Device did not return Stall
NAK Flag (Bit 6)
The NAK Flag bit indicates that the peripheral device replied
with a NAK in the last transaction.
1: Device returned NAK
0: Device did not return NAK
Length Exception Flag (Bit 5)
The Length Exception Flag bit indicates the received data in
the data stage of the last transaction does not equal the
maximum Host Count specified in the Host n Count register. A
Length Exception can either mean an overflow or underflow
and the Overflow and Underflow flags (bits 11 and 10, respec-
tively) should be checked to determine which event occurred.
1: An overflow or underflow condition occurred
0: An overflow or underflow condition did not occur
Sequence Status (Bit 3)
The Sequence Status bit indicates the state of the last received
data toggle from the device. Firmware is responsible for
monitoring and handling the sequence status. The Sequence
bit is only valid if the ACK bit is set to ‘1’. The Sequence bit is
set to ‘0’ when an error is detected in the transaction and the
Error bit will be set.
1: DATA1
0: DATA0
Timeout Flag (Bit 2)
The Timeout Flag bit indicates if a timeout condition occurred
for the last transaction. A timeout condition can occur when a
device either takes too long to respond to a USB host request
or takes too long to respond with a handshake.
1: Timeout occurred
0: Timeout did not occur
Error Flag (Bit 1)
The Error Flag bit indicates a transaction failed for any reason
other than the following: Timeout, receiving a NAK, or
receiving a STALL. Overflow and Underflow are not
considered errors and do not affect this bit. CRC5 and CRC16
errors will result in an Error flag along with receiving incorrect
packet types.
1: Error detected
0: No error detected
Bit # 15 14 13 12 11 10 9 8
Field
Reserved Overflow
Flag
Underflow
Flag
Reserved
Read/Write - - - - R R - -
Default 0 0 0 0 0 0 0 0
Bit # 7 6 5 4 3 2 1 0
Field
Stall
Flag
NAK
Flag
Length
Exception
Flag
Reserved Sequence
Status
Timeout
Flag
Error
Flag
ACK
Flag
Read/Write R R R - R R R R
Default 0 0 0 0 0 0 0 0
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