Fujitsu 8FX User Manual

MB95630H Series
516 FUJITSU SEMICONDUCTOR LIMITED MN702-00009-2v0-E
CHAPTER 24 I
2
C BUS INTERFACE
24.7 Registers
[bit2] SPE: STOP detection interrupt enable bit
This bit enables or disables the STOP detection interrupt.
When this bit and the SPF bit are both set to "1", a STOP detection interrupt request is generated.
[bit1] WUF: MCU standby mode wakeup interrupt request flag bit
This bit detects an MCU standby mode wakeup in stop mode or watch mode.
When this bit and the IBCR0n:WUE bit are both set to "1", a wakeup interrupt request is generated.
With the wakeup function enabled (WUE = 1), when a START condition is detected, the WUF bit is set to
"1".
When read by the read-modify-write (RMW) type of instruction, this bit always returns "1".
[bit0] WUE: MCU standby mode wakeup function enable bit
This bit enables or disables the MCU standby mode wakeup function in stop mode or watch mode.
In stop mode or watch mode, when this bit is set to "1" and a START condition is generated, a wakeup
interrupt request is generated to start the I
2
C operation.
Notes:
• Write "1" to this bit right before the MCU enters stop mode or watch mode. To ensure that the I
2
C operation
can restart immediately after the MCU wakes up from stop mode or watch mode, clear (write "0" to) this bit
as soon as possible.
• When a wakeup interrupt request is generated, the MCU wakes up after the oscillation stabilization wait time
elapses. In order to prevent data loss from occurring immediately after the MCU wakes up, after 100 µs
(assuming that the minimum oscillation stabilization wait time is 100 µs) elapses since a wakeup caused by
the start of I
2
C transmission (upon detection of the falling edge of SDAn), the SCLn must rise in the first
cycle and the first bit must be received as data.
• In standby mode of the MCU, the status flags, state machine, and I
2
C bus output for the I
2
C function keep
their states existing before the MCU entered standby mode. To prevent a hang-up of the entire I
2
C bus system,
ensure that IBSRn:BB is set to "0" before making the MCU enter standby mode.
• The wakeup function does not support the transition of the MCU to stop mode or watch mode with the BB
bit set to "1". When the MCU enters stop mode or watch mode with the BB bit set to "1", a bus error occurs
upon detection of a START condition.
• The wakeup function is effective only when the MCU is in stop mode or watch mode.
Note:
The values of the AACKX, INTS, and WUE bits in the IBCR0n register become "0" and
non-writable either when the I
2
C operation is disabled (ICCRn:EN = 0) or when a bus
error occurs (IBCR1n:BER = 1).
bit2 Details
Writing "0" Disables the STOP detection interrupt.
Writing "1" Enables the STOP detection interrupt.
bit1 Details
Reading "0" Indicates that no START condition has been detected.
Reading "1" Indicates that a START condition has been detected.
Writing "0" Clears this bit.
Writing "1" Has no effect on operation.
bit0 Details
Writing "0" Disables the MCU standby mode wakeup function in stop mode or watch mode.
Writing "1" Enables the MCU standby mode wakeup function in stop mode or watch mode.

Fujitsu 8FX Specifications

General

Brand	Fujitsu
Model	8FX
Category	Computer Hardware
Language	English