r8a66597 Renesas Electronics Corporation., r8a66597 Datasheet - Page 100

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

R8A66597FP/DFP/BG
2.17.11 Response PID bit (PID)
R e v 1 . 0 1
For this bit, set a response of the controller in each pipe by the software.
The default value of this bit is "NAK". While executing a USB transfer by the pipe, modify this bit to "BUF". The basic
operations (operations when there is no error in the communication packet) of this controller for each setup value of
the PID bit are given in Table 2.19 and Table 2.20.
If the pipe is in USB communication, when this bit is modified from "BUF" to "NAK" by the software, after writing "NAK",
to check whether the USB transfer of pipe is actually shifted to "NAK" status, and check whether "PBUSY=1". However,
when the controller modifies this bit to "NAK", it is not necessary to use the software to check the PBUSY bit.
In following cases, the controller modifies the value of this bit:
(1) When the pipe is receiving and when the software has written "1" to the SHTNAK bit of the pipe, the controller sets
"PID=NAK" upon identifying the transfer end.
(2) For the pipe, when the data packet of payload exceeding the maximum packet size is received, the controller sets
"PID=STALL(11)".
(3) When the Peripheral Controller function is selected and when the USB bus reset is detected, the controller sets
"PID=NAK".
(4) When the Host Controller function is detected and when a reception error such as a CRC error is detected
continuously three times, the controller sets "PID=NAK".
(5) When the Host Controller function is selected and when a STALL handshake is received, the controller sets
"PID=STALL(11)".
Write "10" to shift from "PID=NAK("00")" status to "PID=STALL" status. Write "11" to shift from BUF("01") status to
STALL status. First write "10" and then write "00" to shift form "STALL(11)" to NAK status. First, shift to NAK status and
then to BUF status to shift from STALL status to BUF status.
O c t 1 7 , 2 0 0 8
p a g e 1 0 0 o f 1 8 3