Fujitsu MB96300 series Hardware Manual page 810

CHAPTER 30 USB Mini-host
30.5.5 Handshake Packet
Transmitter and receiver are informed of their own status via handshake packet.
■ Handshake Packet
The receiver transmits one of ACK, NAK, and STALL in an handshake packet to inform the data
transmitter whether it can receive data properly or not. When the USB circuit receives a
handshake packet, it sets the HERR:HS bit. When the handshake packet is transmitted, the
transmitted handshake packet sets the HERR:HS bit also.
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