Datasheet

Table Of Contents
Section 15 Universal Serial Bus Interface (USB)
REJ09B0140-0900 Rev. 9.00 Page 597 of 846
Sep 16, 2010
H8S/2215 Group
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Specify IRQ6 to falling edge sensitive
(Set IRQ6E in IER to 1)
(Write IRQ6SCB and A in ISCRH to 01)
Cancel USB module stop mode
(Clear MSTPB0 in MSTPCRB to 0)
Enter USB module stop state
(Stop MSTPB0 in MSTPCRB to 1)
USB communication operations can be
restarted by using several USB registers
Clear SPRSi in UIFR3 to 0
Set SFME in UCTLR to 1
Mask all interrupts with LDC instruction, etc.*
Set IRQ6E in IER to 1*
Unmask all interrupts with LDC instruction, etc.*
Enter software standby mode*
(Execute SLEEP instruction)
IRQ6 = Low (falling edge output)
Set IRQ6F in ISR to 1
Set SPRSi and SPRSs in UIFR3 to 1
Confirm SPRSs in UIFR3 as 1
Clear IRQ6E in IER to 0
*
Clear SPRSi in UIFR3 to 0
Clear SFME in UCTLR to 0
Detect USB bus suspend state
USPND pin = High
Procedure to enter software standby mode Procedure to cancel software standby mode
Detect USB bus resume
USPND pin = Low
All USB module internal clocks stop
USB module internal clock operation starts
Wait 2 ms for USB operation clock to stabilize
(Wait for CK48READY
in UIFR3 is set to 1)
All LSI clocks stop
IRQ6 = High
IRQ6 = High
Cancel software standby mode
Wait for system clock stabilization time
(For external clock: 16 states min)
(For crystal oscillator clock: 4 ms min)
Enter active mode
(LSI internal clock starts oscillation)
IRQ6 = Low (falling edge output)
Set IRQ6F in ISR to 1
Set SPRSi in UIFR3 to 1
Clear SPRSs in UIFR3 to 0
Set CK48READY in UIFR3 to 1
(USB operating clock stabilized)
Detect SOF packet
Set SOF in UIFR3 to 1
: Indicates operations to be done
by firmware.
Guide to Flowchart Figures
: Indicates operations to be
automatically done by hardware
in this LSI.
Note: * Interrupts should be masked from when the IRQ6 interrupt is received until the SLEEP instruction is executed.
Finally, unmask the interrupts using the LDC instruction or the like and execute the SLEEP instruction immediately
afterward.
Figure 15.36 Transition to and from Software Standby Mode