CY7C67300
Register Description
The Host n Count register is used to hold the number of bytes (packet length) for the current transaction. The maximum packet length is 1023 bytes in ISO mode. The Host Count value is used to determine how many bytes to transmit, or the maximum number of bytes to receive. If the number of received bytes is greater then the Host Count value then an overflow condition is flagged by the Overflow bit in the Host n Endpoint Status register.
Port Select (Bit 14)
The Port Select bit selects which of the two active ports is selected and is summarized in Table 51.
1:Port 1B or Port 2B is enabled
0:Port 1A or Port 2A is enabled
Host n Endpoint Status Register [R]
■Host 1 Endpoint Status Register 0xC086
■Host 2 Endpoint Status Register 0xC0A6
Table 52. Host n Endpoint Status Register
Table 51. Port Select Definition
Port Select | Host/Device 1 | Host/Device 2 | |
Active Port | Active Port | ||
| |||
0 | A | A | |
|
|
| |
1 | B | B | |
|
|
|
Count (Bits [9:0])
The Count field sets the value for the current transaction data packet length. This value is retained when switching between host and device mode, and back again.
Reserved
Write all reserved bits with ’0’.
Bit # | 15 | 14 |
| 13 | 12 | 11 | 10 | 9 |
| 8 |
Field |
| Reserved |
|
| Overflow | Underflow |
| Reserved | ||
|
|
|
|
| Flag | Flag |
|
|
| |
Read/Write | - | - |
| - | - | R | R | - |
| - |
Default | 0 | 0 |
| 0 | 0 | 0 | 0 | 0 |
| 0 |
Bit # | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| Stall | NAK | Length | Reserved | Sequence | Timeout | Error | ACK |
Field | Flag | Flag | Exception |
| Status | Flag | Flag | Flag |
|
| Flag |
|
|
|
|
| |
Read/Write | R | R | R | - | R | R | R | R |
Default | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
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 must 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 than the maximum length specified in the Host n Count register. The Underflow Flag must 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 that 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, respectively) must be checked to determine which event occurred.
1:An overflow or underflow condition occurred
0:An overflow or underflow condition did not occur
Document #: | Page 31 of 99 |
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