SH7263 Datasheet, PDF (1392/1862 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7260 Series

Section 25 USB 2.0 Host/Function Module (USB)
SOF
Normal transfer
Token corrupted
Packet inserted
Frame misaligned
Frame misaligned
Token delayed
Token
Token
Token
Token
Token
Token
Token
Token
Token
1
Token
1 Token
Token
1 Token
Token
Token
Token
Token
1 Token
1 Token
Token
Token
Token
1
1
Token
Figure 25.19 Example of an Interval Error Being Generated when IITV = 1
25.4.9 SOF Interpolation Function
When the function controller function is selected and if data could not be received at intervals of 1
ms (when using full-speed operation) or 125 μs (when using high-speed operation) because an
SOF packet was corrupted or missing, this module interpolates the SOF. The SOF interpolation
operation begins when USBE = 1, SCKE = 1 and an SOF packet is received. The interpolation
function is initialized under the following conditions.
• Power-on reset
• Software reset
• USB bus reset
• Suspended state detected
Also, the SOF interpolation operates under the following specifications.
• 125 μs/1 ms conforms to the results of the reset handshake protocol.
• The interpolation function is not activated until an SOF packet is received.
• After the first SOF packet is received, either 125 μs or 1 ms is counted with the USB clock of
48 MHz, and interpolation is carried out.
• After the second and subsequent SOF packets are received, interpolation is carried out at the
previous reception interval.
• Interpolation is not carried out in the suspended state or while a USB bus reset is being
received. (With suspended transitions in high-speed operation, interpolation continues for 3 ms
after the last packet is received.)
Rev. 2.00 Mar. 14, 2008 Page 1358 of 1824
REJ09B0290-0200