h8s-2158 Renesas Electronics Corporation., h8s-2158 Datasheet - Page 668

• Manufacturer Part Number: h8s-2158
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 18 Universal Serial Bus Interface (USB)
Rev. 3.00 Jan 25, 2006 page 616 of 872
REJ09B0286-0300
Note: * When an EP4TS interrupt is specified as a USBIB or USBIC interrupt according to the INTSELR0 setting, the corresponding interrupt occurs.
Figure 18.12 Operation on Receiving an IN Token (EP4-IN: Initial FIFO Is Full)
Receive an IN data
Send an IN token
In this case, if a USBIB or USBIC interrupt occurs, interrupt source determination process is not required. (Note that TSFR0 must be accessed
to clear the flags.)
When a NAK handshake is received from the host, the RFU pointer must be rewound to generate an EP4TF interrupt. This EP4TF interrupt
must be handled in the same way as when an IN token is received while the FIFO is empty since an EP4TF interrupt caused by a NAK
handshake and that caused by an IN token are difficult to be distinguished.
Setting the EP4TE bit to 1 to generate data write (pre-read) to the transmit buffer is necessary.
handshake packet
packet (64 bytes)
Send an ACK
USB Host
packet
Receive an IN token packet
Send ACK to the slave
USB Function Core
packet (64 bytes)
Send an IN data
Receive ACK
CPU
Request a USBID interrupt
Read data from the EP4
(pre-read) and request
Write data to the EP4
the RFU transmission
transmission buffer
Request to modify
transmission buffer
Request the RFU
the RFU pointer
Core Interface
transmission
(EP4TS) *
Read the RAM-FIFO, send
Read the RAM-FIFO, send
an EP4TS interrupt occurs
Read the RFU pointer and
Read USBIFR0 and check
RAM-FIFO for the number
Read TSFR0 and check if
written to, and modify the
Modify the RFU pointer
Clear the EP2TS bit of
if a TS interrupt occurs
of bytes which can be
ACK, and write to the
ACK, and write to the
Set the EP4TE bit of
Complete the USBID
interrupt processing
interrupt processing
Initiate the USBID
write data to EP4
and send ACK
transmit buffer
transmit buffer
PTTER0 to 1
TSFR0 to 0
RFU pointer
Slave CPU
or not
or not