
DocID024597 Rev 5
183/1830
RM0351
Power control (PWR)
198
5.4.4
Power control register 4 (PWR_CR4)
Address offset: 0x0C
Reset value: 0x0000 0000. This register is not reset when exiting Standby modes and with
the PWRRST bit in the RCC_APB1RSTR1 register.
Access: Additional APB cycles are needed to access this register vs. a standard APB
access (3 for a write and 2 for a read).
Bit 10
APC
: Apply pull-up and pull-down configuration
When this bit is set, the I/O pull-up and pull-down configurations defined in the PWR_PUCRx
and PWR_PDCRx registers are applied. When this bit is cleared, the PWR_PUCRx and
PWR_PDCRx registers are not applied to the I/Os.
Bit 9 Reserved, must be kept at reset value.
Bit 8
RRS
: SRAM2 retention in Standby mode
0: SRAM2 is powered off in Standby mode (SRAM2 content is lost).
1: SRAM2 is powered by the low-power regulator in Standby mode (SRAM2 content is kept).
Bits 7:5 Reserved, must be kept at reset value.
Bit 4
EWUP5
: Enable Wakeup pin WKUP5
When this bit is set, the external wakeup pin WKUP5 is enabled and triggers a wakeup from
Standby or Shutdown event when a rising or a falling edge occurs.The active edge is
configured via the WP5 bit in the PWR_CR4 register.
Bit 3
EWUP4
: Enable Wakeup pin WKUP4
When this bit is set, the external wakeup pin WKUP4 is enabled and triggers a wakeup from
Standby or Shutdown event when a rising or a falling edge occurs. The active edge is
configured via the WP4 bit in the PWR_CR4 register.
Bit 2
EWUP3
: Enable Wakeup pin WKUP3
When this bit is set, the external wakeup pin WKUP3 is enabled and triggers a wakeup from
Standby or Shutdown event when a rising or a falling edge occurs. The active edge is
configured via the WP3 bit in the PWR_CR4 register.
Bit 1
EWUP2
: Enable Wakeup pin WKUP2
When this bit is set, the external wakeup pin WKUP2 is enabled and triggers a wakeup from
Standby or Shutdown event when a rising or a falling edge occurs. The active edge is
configured via the WP2 bit in the PWR_CR4 register.
Bit 0
EWUP1
: Enable Wakeup pin WKUP1
When this bit is set, the external wakeup pin WKUP1 is enabled and triggers a wakeup from
Standby or Shutdown event when a rising or a falling edge occurs. The active edge is
configured via the WP1 bit in the PWR_CR4 register.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Res.
Res.
Res.
Res.
Res.
Res.
VBRS
VBE
Res.
Res.
Res.
WP5
WP4
WP3
WP2
WP1
rw
rw
rw
rw
rw
rw
rw