SH7263 Datasheet, PDF (1349/1862 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7260 Series

Section 25 USB 2.0 Host/Function Module (USB)
(3) BEMP Interrupt
If a pipe is under the conditions below, this module sets the corresponding bit in BEMPSTS to 1.
In this case, this module generates a BEMP interrupt if software sets the PIPEBEMPE bit in
BEMPENB corresponding to the corresponding pipe and the BEMPE bit in INTENB0 to 1. If
software clears all the bits in BEMPSTS, this module clears the BEMP bit in INTSTS0.
1. When the transmitting direction (writing to the buffer memory) has been set
When all of the data stored in the buffer memory has been transmitted
If the buffer memory is being used as a double buffer, however, the following conditions
should be met.
⎯ A BEMP interrupt is generated if the buffer on one side is empty and transmitting of data
from the buffer on the other side has been completed.
⎯ A BEMP interrupt is generated if data consisting of less than eight bytes is being written to
the buffer on one side, and transmitting of data on the other side of the buffer has been
completed.
2. When the receiving direction (reading from the buffer memory) has been set
If the size of the data packet that was received exceeded the maximum packet size and the
maximum packet size is not set to 0 (MXPS ≠ 0), this module sets the PID bit of the
corresponding pipe to STALL.
Figure 25.5 shows the timing at which a BEMP interrupt is generated when the function controller
function has been selected.
(1) Data transmission
USB bus
IN token packet
Data packet
ACK handshake
BEMP interrupt
(2) Data reception
USB bus
OUT token packet
Data packet
STALL handshake
BEMP interrupt
Figure 25.5 Timing at which BEMP Interrupt is Generated when Function Controller
Function is Selected
Rev. 2.00 Mar. 14, 2008 Page 1315 of 1824
REJ09B0290-0200