Rev.2.00 Oct 16, 2006 page 163 of 354
REJ09B0340-0200
M30245 Group
2. USB function
(2) USB Suspend Function
In the M30245 group, the USB suspend status flag (SUSPEND) of USB power management register
(address 0282
16
) is set to “1” when the suspend signal has been received from the host CPU (or not
detected any bus activity on the D+/D- line for at least 3ms). Simultaneously, the USB suspend inter-
rupt request occurs.
To shift into the USB suspend state, control the USB function control unit in the following procedure.
Further, for changes in frequency synthesizer control register (address 03DC
16
) or system clock con-
trol register1 (address 0007
16
), clearing the corresponding bit of protect register (address 000A
16
) is
required.
●
USB Suspend Mode Control
1: Set USB clock enable bit of USB control register to “0”. Do not write to USB internal registers (other
than the USBC, USBAD, and frequency synthesizer related registers) when the USB clock has
been disabled in the suspend state.
2: During the bus power supply operation as a low-power device, control it to reduce the total driving
current to 500
µ
A or below (or 2.5mA or below when remote wakeup has been enabled as a high-
power device by the host CPU). For details of the power control in suspend, refer to USB2.0
specification.
3: Set frequency synthesizer enable bit of frequency synthesizer control register to “0”.
4: Set the return interrupt from the USB suspend state. Set USB resume interrupt control register
(address 0058
16
). (When remote wakeup has been enabled, enable interrupt control register of the
peripheral functions used in remote wakeup.)
5: Set I flag to “1”.
6: Stop the system clock by setting all clock stop control bit (bit 0 of CM1) to 1.
7: During the bus power supply operation, after setting the low-power consumption mode by dis-
abling interrupts that are not used in return from the USB suspend state, etc., execute the low-
power consumption mode.
Note: When the device is in self-powered operation, the above control is not required.
Содержание M16C FAMILY
Страница 12: ...Chapter 1 Hardware...
Страница 13: ...See M30245 group datasheet...
Страница 14: ...Chapter 2 Peripheral Functions Usage...
Страница 303: ...THIS PAGE IS BLANK FOR REASONS OF LAYOUT...
Страница 304: ...Chapter 3 Examples of Peripheral Functions Applications...
Страница 340: ...Chapter 4 External Buses...
Страница 361: ...THIS PAGE IS BLANK FOR REASONS OF LAYOUT...
Страница 362: ...Chapter 5 Standard Characteristics...
Страница 369: ...1753 Shimonumabe Nakahara ku Kawasaki shi Kanagawa 211 8668 Japan M30245 Group REJ09B0340 0200 User s Manual...