Cypress enCoRe CY7C63310 - Manual (Page 61)

CY7C63310, CY7C638xx
Document 38-08035 Rev. *K Page 61 of 83
The three data buffers are used to hold data for both IN and OUT transactions. Each data buffer is 8 bytes long.
The reset values of the Endpoint Data Registers are unknown.
Unlike past enCoRe parts the USB data buffers are only accessible in the IO space of the processor.
22. USB Mode Tables
22.1 Mode Column
The 'Mode' column contains the mnemonic names given to the
modes of the endpoint. The mode of the endpoint is determined
by the 4-bit binaries in the 'Encoding' column as discussed in the
following sections. The Status IN and Status OUT represent the
status IN or OUT stage of the control transfer.
22.2 Encoding Column
The contents of the 'Encoding' column represent the Mode
Bits [3:0] of the Endpoint Mode Registers ( Table 21-3 on page 59
and Table 21-4 on page 60). The endpoint modes determine how
the SIE responds to different tokens that the host sends to the
endpoints. For example, if the Mode Bits [3:0] of the Endpoint 0
Mode Register are set to '0001', which is NAK IN/OUT mode, the
SIE sends an ACK handshake in response to SETUP tokens and
NAK any IN or OUT tokens.
Table 21-7. Endpoint 2 Data (EP2DATA) [0x60-0x67] [R/W]
Bit # 7 6 5 4 3 2 1 0
Field Endpoint 2 Data Buffer [7:0]
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Default Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown
The Endpoint 2 buffer is comprised of 8 bytes located at address 0x60 to 0x67.
Mode Encoding SETUP IN OUT Comments
DISABLE 0000 Ignore Ignore Ignore Ignore all USB traffic to this endpoint. Used by Data and
Control endpoints.
NAK IN/OUT 0001 Accept NAK NAK NAK IN and OUT token. Control endpoint only.
STATUS OUT ONLY 0010 Accept STALL Check STALL IN and ACK zero byte OUT. Control endpoint
only.
STALL IN/OUT 0011 Accept STALL STALL STALL IN and OUT token. Control endpoint only.
STATUS IN ONLY 0110 Accept TX0 byte STALL STALL OUT and send zero byte data for IN token. Con-
trol endpoint only.
ACK OUT – STATUS
IN
1011 Accept TX0 byte ACK ACK the OUT token or send zero byte data for IN token.
Control endpoint only.
ACK IN – STATUS
OUT
1111 Accept TX Count Check Respond to IN data or Status OUT. Control endpoint
only.
NAK OUT 1000 Ignore Ignore NAK Send NAK handshake to OUT token. Data endpoint
only.
ACK OUT (STALL = 0) 1001 Ignore Ignore ACK This mode is changed by the SIE to mode 1000 on is-
suance of ACK handshake to an OUT. Data endpoint
only.
ACK OUT (STALL = 1) 1001 Ignore Ignore STALL STALL the OUT transfer.
NAK IN 1100 Ignore NAK Ignore Send NAK handshake for IN token. Data endpoint only.
ACK IN (STALL = 0) 1101 Ignore TX Count Ignore This mode is changed by the SIE to mode 1100 after
receiving ACK handshake to an IN data. Data endpoint
only.
ACK IN (STALL = 1) 1101 Ignore STALL Ignore STALL the IN transfer. Data endpoint only.
Reserved 0101 Ignore Ignore Ignore These modes are not supported by SIE. Firmware must
not use this mode in Control and Data endpoints.
Reserved 0111 Ignore Ignore Ignore
Reserved 1010 Ignore Ignore Ignore
Reserved 0100 Ignore Ignore Ignore
Reserved 1110 Ignore Ignore Ignore
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