ST72361
POWER SAVING MODES (Cont’d)
8.6.1 Register Description
AWUFH CONTROL/STATUS REGISTER
(AWUCSR)
Read / Write (except bit 2 read only)
Reset Value: 0000 0000 (00h)
7
0
0: AWUFH (Auto Wake-Up From Halt) mode disa-
bled
1: AWUFH (Auto Wake-Up From Halt) mode ena-
bled
AWUFH PRESCALER REGISTER (AWUPR)
Read / Write
Reset Value: 1111 1111 (FFh)
0
0
0
0
Bits 7:3 = Reserved.
0
AWU AWU AWU
F M EN
7
0
AWU AWU AWU AWU AWU AWU AWU AWU
PR7 PR6 PR5 PR4 PR3 PR2 PR1 PR0
Bit 2 = AWUF Auto Wake-Up Flag
This bit is set by hardware when the AWU module
generates an interrupt and cleared by software on
reading AWUCSR.
0: No AWU interrupt occurred
1: AWU interrupt occurred
Bit 1 = AWUM Auto Wake-Up Measurement
This bit enables the AWU RC oscillator and con-
nects its output to the ICAP1 input of the 16-bit tim-
er. This allows the timer to be used to measure the
AWU RC oscillator dispersion and then compen-
sate this dispersion by providing the right value in
the AWUPR register.
0: Measurement disabled
1: Measurement enabled
Bit 0 = AWUEN Auto Wake-Up From Halt Enabled
This bit enables the Auto Wake-Up From Halt fea-
ture: once HALT mode is entered, the AWUFH
wakes up the microcontroller after a time delay de-
fined by the AWU prescaler value. It is set and
cleared by software.
Table 11. AWU Register Map and Reset Values
Bits 7:0 = AWUPR[7:0] Auto Wake-Up Prescaler
These 8 bits define the AWUPR Dividing factor (as
explained below:
AWUPR[7:0]
00h
01h
...
FEh
FFh
Dividing factor
Forbidden (See note)
1
...
254
255
In AWU mode, the period that the MCU stays in
Halt Mode (tAWU in Figure 30) is defined by
tAWU
=
64 × AWUPR × ------------1-------------
fAWURC
+ tRCSTRT
This prescaler register can be programmed to
modify the time that the MCU stays in Halt mode
before waking up automatically.
Note: If 00h is written to AWUPR, depending on
the product, an interrupt is generated immediately
after a HALT instruction or the AWUPR remains
unchanged.
Address
(Hex.)
002Bh
002Ch
Register
Label
7
6
5
4
3
2
1
0
AWUCSR
Reset Value
AWUPR
Reset Value
0
AWUPR7
1
0
AWUPR6
1
0
AWUPR5
1
0
AWUPR4
1
0
AWUPR3
1
AWUF
0
AWUPR2
1
AWUM
0
AWUPR1
1
AWUEN
0
AWUPR0
1
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