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Section 26 USB 2.0 Host/Function Module
Page 1486 of 2108 R01UH0134EJ0400 Rev. 4.00
Sep 24, 2014
SH7262 Group, SH7264 Group
(2) NRDY Interrupt
On generating the internal NRDY interrupt request for the pipe whose PID bits are set to BUF,
this module sets the corresponding PIPENRDY bit in NRDYSTS to 1. If the corresponding bit in
NRDYENB is set to 1, this module sets the NRDY bit in INTSTS0 to 1, allowing the USB
interrupt to be generated.
The following describes the conditions on which this module generates the internal NRDY
interrupt request for a given pipe.
However, the internal NRDY interrupt request is not generated during setup transaction execution
when the host controller function is selected. During setup transactions when the host controller
function is selected, the SACK or SIGN interrupt is detected.
The internal NRDY interrupt request is not generated during status stage execution of the control
transfer when the function controller function is selected.
(a) When the host controller function is selected and when the connection is used in which
no split transactions occur
(i) For the pipe in the transmitting direction:
On any of the following conditions, this module detects the NRDY interrupt.
For the pipe for isochronous transfers, when the time to issue an OUT token comes in a
state in which there is no data to be transmitted in the FIFO buffer.
In this case, this module transmits a zero-length packet following the OUT token, setting
the corresponding PIPENRDY bit and the OVRN bit to 1.
During communications other than setup transactions using the pipe for the transfers other
than isochronous transfers, when any combination of the following two cases occur three
consecutive times: 1) no response is returned from the peripheral device (when timeout is
detected before detection of the handshake packet from the peripheral device) and 2) an
error is detected in the packet from the peripheral device.
In this case, this module sets the corresponding PIPENRDY bit to 1 and modifies the
setting of the PID bits of the corresponding pipe to NAK.
During communications other than setup transactions, when the STALL handshake is
received from the peripheral device (including the STALL handshake in response to PING
in addition to the STALL handshake in response to OUT).
In this case, this module sets the corresponding PIPENRDY bit to 1 and modifies the
setting of the PID bits of the corresponding pipe to STALL (11).