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CHAPTER 12 USB HOST
12.4 Register of USB HOST
12.4.8
EOF Setting Register (HEOF)
The EOF setting register (HEOF) is a register that sets a time period for which a token is
inhibited before the execution of the SOF token. If the data of the SOF timer turns out to
be lower than data in the HEOF register as a result of comparing both, and any of an IN
token, OUT token, and SETUP token execution requests is made, it will be run after the
SOF token is executed. This prevents an SOF token generated by hardware and other
tokens from being simultaneously executed. The unit of time for the HEOF register is
one-bit transfer time.
■ EOF Setting Register (HEOF)
Figure 12.4-8 Bit Configuration of EOF Setting Register (HEOF)
EOF setting register
bit
Address: 0000CA
H
→
Read/Write
→
Initial value
Reset On/Off at UDCC RST bit →
bit
Address: 0000CB
H
→
Read/Write
→
Initial value
Reset On/Off at UDCC RST bit →
[bit 15, bit 14] Reserved
These are reserved bits. The reading is undefined. The writing does not influence the operation.
[bit 13 to bit 0] EOF1,EOF0:EOF
Set a time period during which the execution of a token is inhibited before the execution of SOF. Set a
margin that is longer than one packet length. The unit is one bit forwarding time. It is not initialized
with the RST bit in the UDC control register (UDCC). To update them, you must set the RST bit in the
UDC control register (UDCC) to "0".
For the MAXPKT=64 byte and Full Speed of set example
(Token_length + packet_length + header + CRC)×7/6 + Turn_around_time
=(34bit + 546bit)×7/6 + 36bit = 712.7bits
As the above is true, specify 2C9
266
7
6
5
15
14
13
Reserved
(-)
(x)
(-)
.
H
FUJITSU MICROELECTRONICS LIMITED
4
3
2
EOF0
(R/W)
(00000000
)
B
( )
12
11
10
EOF1
(R/W)
(000000
)
B
( )
MB90335 Series
1
0
HEOF
9
8
HEOF
CM44-10137-6E
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