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Section 26 USB 2.0 Host/Function Module
Page 1514 of 2108 R01UH0134EJ0400 Rev. 4.00
Sep 24, 2014
SH7262 Group, SH7264 Group
Buffer memory PIPEBUF registers
64 bytes
64 bytes
64 bytes
128 bytes
BUFSIZE = 0,
DBLB = 0
BUFSIZE = 0,
DBLB = 1
BUFSIZE = 1,
DBLB = 0
Figure 26.10 Example of Buffer Memory Settings
(f) Buffer Memory Operation (Continuous Transfer Setting)
Either the continuous transfer mode or the non-continuous transfer mode can be selected, using the
CNTMD bit in DCPCFG and PIPECFG. This selection is valid for PIPE1 to PIPE5 and DCP.
The continuous transfer mode function is a function that sends and receives multiple transactions
in succession. When the continuous transfer mode is set, data can be transferred without interrupts
being issued to the CPU, up to the buffer sizes assigned for each of the pipes.
In the continuous sending mode, the data being written is divided into packets of the maximum
packet size and sent. If the data being sent is less than the buffer size (short packet, or the integer
multiple of the maximum packet size is less than the buffer size), BVAL = 1 must be set after the
data being sent has been written.
In the continuous reception mode, interrupts are not issued during reception of packets up to the
buffer size, until the transaction counter has ended, or a short packet is received.
Table 26.22 describes the relationship between the transfer mode settings by CNTMD bit and the
timings at which reading data or transmitting data from the FIFO buffer is enabled.