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SA-1110 Developer’s Manual 291
Peripheral Control Module
Note: To read the data: a) read the UDCWC-WC bits, b) read UDCCD0, c) re-read the UDCWC-WC bits
and d) keep reading UDCCD0 followed by the UDCWC-WC bits until the UDCWC-WC bits
decrement.
11.8.11 UDC Endpoint 0 Write Count Register (UDCWC)
UDCWC has a 4-bit “Write Count” field that can be read when a packet has been received from the
Host by Endpoint 0. UDCWC can be used to determine how many bytes to read out of UDCD0.
When data is present in the Control FIFO, UDCWC should read between 1 and 8.
0h 8000 001C UDCD0 Read/Write
7 6 5 4 3 2 1 0
Bottom of Endpoint 0 FIFO
Reset
? ? ? ? ? ? ? ?
Read Access
7 6 5 4 3 2 1 0
Top of Endpoint 0 FIFO
Reset
? ? ? ? ? ? ? ?
Write Access
Bits Name Description
7..0 DATA
Top/bottom of Endpoint 0 FIFO data.
Read – Bottom of Endpoint 0 FIFO data.
Write – Top of Endpoint 0 FIFO data.
0h 8000 0020 UDCWC Read-Only
7 6 5 4 3 2 1 0
Reserved Write Count
Reset
0 0 0 0 0 0 0 0
Bits Name Description
3..0 WC
Endpoint 0 write count (read-only).
4-bit field representing the number of bytes in the Endpoint 0 FIFO.
7..4 —
Reserved.
Always reads zero.