Suspend Signal Interrupt; Usb Sof (Start Of Frame) Interrupt; Usb Function Control Unit Initialization - Renesas M16C Series User Manual

M30240 Group

3.2.7.4 Suspend Signal Interrupt

An interrupt request occurs when the interrupt status flag of the USB Suspend Interrupt Status register
(SUSPIC) is "1."
The USB Suspend Interrupt Status flag is set to "1" when the USB Suspend signal is received (when
there is no activity for at least 3ms on the D+/D- line).

3.2.7.5 USB SOF (Start of Frame) Interrupt

This interrupt is used to control isochronous transfers. Endpoint 1-4 can be used. When a SOF packet
is received from the host CPU, a USB SOF interrupt request occurs. The interrupt request bit and its'
priority level select bit are set in the SOF Interrupt Control register (SOFIC).

3.2.8 USB Function Control Unit Initialization

The initialization of the USB function control unit for the M30240 Group is shown below. The initialization
routine is:
• Use the Frequency Synthesizer to generate 48MHz required for the f
• Enable the USB Function Control unit.
• Initialize each endpoint.
Figure 3.26 shows a block diagram of the frequency synthesizer circuit; Figure 3.27 through Figure 3.30
show the procedures for setting the registers.
f(Xin)
Prescaler
03DE
16
Figure 3.26: Frequency Synthesizer Circuit Block Diagram
Rev.1.00 Sep 24, 2003 Page 313 of 360
Frequency
f
PIN
Multiplier
FSP FSM
03DC
03DD
16
USB
f
USB
EN
USBC5
f
SYN
f
Frequency
VCO
Divider
LS
8 Bit
FSC FSD
03DF 03DB
16 16
Data Bus
Universal Serial Bus
.
FSCCR0
FSCCR
16