R8A66597BG RENESAS [Renesas Technology Corp], R8A66597BG Datasheet - Page 92

• Manufacturer Part Number: R8A66597BG
• Description: ASSP (USB2.0 2 Port Host/1 Port Peripheral Controller)
• Manufacturer: RENESAS [Renesas Technology Corp]

R8A66597FP/DFP/BG
2.16.14.1 When the Host Controller function is selected
R e v 1 . 0 1
In case of isochronous or Interrupt transfer type of the selected pipe, values can be written to this bit. The controller
controls the token issue interval by the setup value of this bit. The controller issues a token for the selected pipe in
one interval with a (micro) frame for 2^IITV times.
The controller counts the interval in 1ms frames for the pipe used during the communication between
Full-/Low-Speed Peripheral Devices connected to a Hi-Speed HUB.
The controller starts counting the token issue spacing from the next (micro) frame after the software writes the PID
bit to "BUF".
If the transfer type of the selected pipe is an isochronous or interrupt, the controller executes the following operations
along with the control of the token issue interval. If the transfer type is isochronous, the controller also issues the
token when the NRDY interrupt issue conditions are fulfilled.
(1) If the selected pipe is isochronous-IN transfer pipe
(2) If the selected pipe is an isochronous-Out transfer pipe
O c t 1 7 , 2 0 0 8
When an In-token is issued and the packet is not received normally from the Peripheral device (if there is no
response or packet error), an NRDY interrupt is issued.
Since the FIFO buffer is full (due to reasons like the reading of data from FIFO buffer by the software (DMAC) is
slow), the controller sets "1" to the OVRN bit and issues the NRDY interrupt when it cannot receive the data and
reaches the In-token issue timing.
When the FIFO buffer contains no data that can be sent (due to reasons like the writing of data in FIFO buffer by
the software (DMAC) is slow) and it reaches the Out-token issue timing, the controller displays "1" in the OVRN
bit, issues the NRDY interrupt and a zero-length packet is sent.
Interval counting start
PID bit setup value
Token issue flag
-: Not issued)
(0: Issued
USB us
p a g e 9 2 o f 1 8 3
Figure 2.1 Token issue flag when "IITV=0"
Figure 2.2 Token issue flag when "IITV=1"
Interval counting start
PID bit setup value
Token issue flag
-: Not issued)
(0: Issued
USB bus
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