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M30245 Group
(6) USB Transmit (Endpoints 1 to 4 IN): Example
The endpoints 1 to 4 IN transmit packet prepare routine (continuous transfer disable) is shown in
Figure 2.8.49. In addition to packet prepare process, error process by the UNDER_RUN flag is re-
quired in isochronous transfer.
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1. Confirming of whether there is a space which is equal to one packet in the IN FIFO:
(b15)
b7
0
2. Writing of the transmit data equal to one packet data (Note 1) to the IN FIFO.
(b15)
b7
Note 1: The packet data is one buffer data in continuous transfer mode.
3. Setting of the SET_IN_BUF_RDY bit to "1" and completion of one packet data (Note 2) prepare.
(b15)
b7
0
Note 2: The packet data is one buffer data in continuous transfer mode.
Note 3: When the AUTO_SET bit is set to "1", this bit is automatically set to "1" when the data count set by
Figure 2.8.49. Endpoint 1 to 4 IN packet prepare routine
Rev.2.00 Oct 16, 2006
REJ09B0340-0200
Process of USB endpoint x IN packet prepare
check the IN_BUF_STS0 and the IN_BUF_STS1.
(b8)
b0
b7
0
0
0
0
IN FIFO full
(b8)
b0
b7
(b8)
b0
b7
0
0
0
0
maximum packet size register is written to the IN FIFO. When the AUTO_SET bit is set to "0" or the
AUTO_SET bit is set to "1" and it is a short packet (data packet which is smaller than maximum packet size),
this bit is set to "1" by software.
Execution of the above 2 and 3 again when the second
packet data is set on the double buffer mode.
page 206 of 354
b0
USB endpoint x IN control and status register
EPxICS (x = 1 - 4) [Address 029E
IN_BUF_STS0 flag
IN_BUF_STS1 flag
b1 b0
0 0 : No data set in the IN buffer
0 1 : Single buffer mode: N/A
Double buffer mode: one data set in the IN buffer
1 0 : N/A
1 1 : Single buffer mode: one data set in the IN buffer
Double buffer mode: two data set in the IN buffer
There is a space in the IN FIFO.
b0
USB endpoint x IN FIFO data register
EPxI (x = 0 - 4) [Address 02E0
Setting of the transmit data
b0
USB endpoint x IN control and status register
0
EPxICS (x = 1 - 4) [Address 029E
SET_IN_BUF_RDY bit
1 : Transmission data set loaded to the IN buffer
(updates IN_BUF_STS0, IN_BUF_STS1 flags)
Completion of packet data prepare
2. USB function
, 02A4
, 02AA
, 02B0
16
16
16
16
, 02E4
, 02E8
, 02EC
, 02F0
16
16
16
16
16
, 02A4
, 02AA
, 02B0
16
16
16
16
]
]
]
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