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TMP92CZ26A
92CZ26A-475
3.16.11 Points to Note and Restrictions
1. Limitation of writing to COMMAND register in special timing
When “STALL” command is issued, ENDPOINT status might be shift to “INVALID”.
To avoid this problem, keep the below routine.
a. BULK (IN/OUT)
In case issue STALL command to endpoint in BULK transfer, be sure to issue
STALL command after stop RD/WR accessing to endpoint; that is UDC returns
NAK in the response of token from host. INT_EPxNAK should be used to detect
NAK transmit.
b. CONTROL OUT with data stage (software response)
If STALL needs to be set for endpoint 0 judging from request after receiving
INT_SETUP interrupt, access to SetupReceived register. After that, issue STALL
command after detecting INT_ENDPOINT0 interrupt.
c. CONTROL OUT without data stage (software response)
If STALL needs to be set for endpoint 0 judging from request after receiving
INT_SETUP interrupt, issue STALL command before access to eop register.
d. CONTROL IN(software response)
If STALL needs to be set for endpoint 0 judging from request after receiving
INT_SETUP interrupt, issue STALL command before set the first transmit data
to host.
2. Limitation of EPx_STATUS<STATUS2:0> when execute USB_RESET command
EPx_STATUS<STATUS2:0> may indicates different condition, if execute
USB_RESET command to the endpoint in the process of token. To avoid this
phenomenon, do not RESET the endpoint in transferring. (It is available in the process
of request that needs USB_RESET to that endpoint.)