r8a66597 Renesas Electronics Corporation., r8a66597 Datasheet - Page 151

• Manufacturer Part Number: r8a66597
• Description: Assp Usb2.0 2 Port Host/1 Port Peripheral Controller
• Manufacturer: Renesas Electronics Corporation.

R8A66597FP/DFP/BG
3.9.4
R e v 1 . 0 1
(2) Receive Start Example 2 (Ex. 1 of when send data is ready after IN token receive start)
(3) Receive Start Example 2 (Ex. 2 of when send data is ready after IN token receive start)
(3) Example of Irregular Period IN Token receive
Receive toke n
Se nd packet
Buffer A
Buffer B
Receive toke n
Send packe t
Buffer A
Buffer B
Receive toke n
Se nd packet
Buffer A
Buffer B
Receive toke n
Se nd packet
Buffer A
Buffer B
(1) Receive Start Example 1 (when send data is ready before IN token receive start)
Isochronous Transfer Send Data Setup when Peripheral Controller function is selected
Note that the interval counter is not initialized in the following conditions.
When the Peripheral Controller function is selected, after data is written to the buffer memory in the isochronous
transmission, the data packet can be sent out in the next frame detected after the SOF packet. This function, called the
isochronous transfer send data setup function, allows the frame that started the send to be specified.
When using the buffer memory as a double buffer and both buffers have been written, only the first buffer memory to
complete the write event is transfer-enabled. Therefore, even when several IN tokens are received in the same frame,
only one packet of data is sent by the buffer memory.
When an IN token is received, if the buffer memory is in the send-enabled state, the data transfer will be sent and a
normal response returned. However, if the buffer memory is not in the send-enabled state, a zero-length packet is sent
and an underrun error occurs.
Figure 3.20 shows a controller send example using the isochronous transfer send data setup function when “IITV=0
(per frame)” is set.
(1) When the PID is set to NAK or STALL
(2) USB bus reset or USB suspend
O c t 1 7 , 2 0 0 8
The interval timer is not stopped at this time. The transaction will be attempted at the next interval.
The IITV bit is not initialized at this time. When the SOF is received, the count starts from the value before the
receive.
SOF
SOF
Empty state
Empty state
Empty state
Empty state
SOF
Empty state
Empty state
Empty state
p a g e 1 5 1 o f 1 8 3
Writing
Writing
Writing
Writing
Figure 3.20 Data Setup Function Operation
IN
IN
Write e nd
Writing
Write end
Writing
length
length
Write end
Writing
Zero-
Zero-
IN
SOF
SOF
SOF
length
Zero-
Tran sfer- enabled
Tran sfer- enabled
Write end
IN
IN
Empty state
Data-A
Data-A
Write end
Write end
Empty state
Empty state
IN
IN
length
length
Zero-
Zero -
Tr ansfer -enabled status
Write end
SOF
SOF
SOF
SOF
Writing
Writing
Tran sfer- enabled status
Tran sfer- enabled
Tran sfer- enabled
sta tus
sta tus
IN
IN
IN
Data-B
Data-B
Write end
Write end
Data-A
Empty state
Empty state
Empty state
SOF
SOF
SOF