Fujitsu F2MC-16LX Hardware Manual page 341

[bit 9, bit 8] HS: Handshake status
It indicates the status of handshake operations between transmission and reception in host mode. It
indicates NULL when handshake operation is not performed due to any reasons such as an error and the
SOF token is completed. It is updated when transmission or reception has been completed. To update
them, you must set the RST bit in the UDC control register (UDCC) to "0".
Table 14.4-1 Handshake
bit9 bit8
0 0
0 1
1 0
1 1
CHAPTER 14 USB Mini-HOST
Handshake
ACK
NAK
STALL
NULL
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