Datasheet

Table Of Contents
Section 15 Universal Serial Bus Interface (USB)
REJ09B0140-0900 Rev. 9.00 Page 599 of 846
Sep 16, 2010
H8S/2215 Group
15.9.14 Pin Processing when USB Not Used
Pin processing should be performed as follows.
DrVCC = Vcc, DrVSS = 0 V, USD+ = USD- = USPND = open state, VBUS = UBPM = 0 V
15.9.15 Notes on Emulator Usage
Using the I/O register window function, or the like, to display UEDR0o, UEDR2o, UEDR3o, and
UEDR4o can cause the EP0oFIFO, EP2oFIFO, EP3oFIFO, and EP4oFIFO read pointers to
malfunction, preventing UEDR0o to UEDR4o and UESZ0o to UESZ4o from being read correctly.
Therefore, UEDR0o to UEDR4o should not be displayed.
15.9.16 Notes on TR Interrupt
Note the following when using the transfer request interrupt (TR interrupt) for IN transfer to EP0i,
EP2i, EP3i, EP4i, or EP5i.
The TR interrupt flag is set if the FIFO for the target EP has no data when the IN token is sent
from the USB host. However, at the timing shown in figure 15.38, multiple TR interrupts occur
successively. Take appropriate measures against malfunction in such a case.
Note: This module determines whether to return NAK if the FIFO of the target EP has no data
when receiving the IN token, but the TR interrupt flag is set only after a NAK handshake
is sent. If the next IN token is sent before PKTE of UTRGx is written to, the TR interrupt
flag is set again.
CPU
Host IN token IN token IN token
Sets TR flag
(Sets the flag again)
Sets TR flag
Determines whether
to return NAK
Transmits data
TR interrupt routine
Clear
TR flag
Writes
transmit data
UTRGx/
PKTE
TR interrupt routine
USB
NAK
Determines whether
to return NAK
NAK
ACK
Figure 15.38 TR Interrupt Flag Set Timing