一、串口低功耗模式介绍6 D& u3 y- O% c$ Q R0 [
1.1 介绍2 A* Y) J) ~2 ?8 q5 b, e8 q
stm32可以通过串口来从stop模式唤醒,如果基于hal库,只要进行一些配置就能使用,这种通过串口唤醒的低功耗模式可以用在带电池的设备上,在需要设备工作的时候才将其唤醒处理事务,处理完后进入stop模式降低功耗。, E2 O" F, c, s" P* a, G2 a
' h$ {9 k1 N/ S; n% B; q. L1.2 三种模式和相关的寄存器# E, y f# Z1 G- T4 P
1.2.1 寄存器 [/ y; n8 o1 K6 z& |. l8 w6 y4 O
1.2.1.1 CR3[21:20] WUS[1:0]
$ w; h! T# ^ ^7 |功能:选择从低功耗模式中断唤醒的标志
* O" Z j" L+ {/ o6 x配置说明: i: }& Z/ j* s
00:地址匹配模式6 H; R7 @0 \4 @
01:保留5 B9 x% y- y8 d/ D( ?
10:检测起始位
6 z" n$ f& N, Y* K. ]% L* J9 w11:RXNE/RXFNE中断1 y" c( R l* |7 ]6 Q
0 U. j- @6 i b5 R4 V0 O6 r
1.2.1.2 CR3[22] WUFIE
3 f) n& _4 }: L5 s( @9 z$ J8 S功能:使能从低功耗模式唤醒
3 R3 W. u# }& z2 |7 ]: q* Y配置说明:( w- f: j; j" s# b. y
0:关闭中断
. `: k$ J) P$ A" l; R1:使能WUF中断,即当ISR的WUF为1时产生一个中断, k9 \6 ^) G: ]+ P+ J
8 M0 H$ A( X1 q ?
1.2.1.3 CR1[1] UESM
5 [$ G0 l0 N( D8 m功能:使能串口的低功耗模式. x6 K" ]( Q6 s `4 p
配置说明:
) T" w9 l0 I7 j+ w$ I! r7 t7 I0:串口不能唤醒低功耗模式
- u% e ]+ a d( r: E Y F5 N1:串口能唤醒低功耗模式# R! W3 `. @7 w' v/ i3 j+ p
4 k( q% M9 v: F1 }+ ]3 y7 H1.2.1.4 PWR_CR1[2:0] LPMS[2:0] B8 O& k% b+ L. \6 H8 \
功能:低功耗模式选择+ j3 R* S0 [) }2 F
配置说明:
: M& a! p4 Q" t/ s6 k- Q000:stop 0模式
1 A$ F1 _2 A @. N6 V001:stop1模式4 o) H. }+ @+ A/ Y' l$ }
010:保留
: l- K. l( \" Q/ A R0 c9 M011:stanby模式. f8 @' w5 k% p( B! i6 M& Q
4 `1 u& t( \! v: P6 y
1.2.1.5 SCB_SCR[2] SLEEPDEEP: D/ _, S% E/ E( z& m2 H
功能:决定处理器在低功耗模式时选择睡眠模式还是深度睡眠模式,SCB寄存器的内容在m0+编程手册里。3 o. v7 }7 l' Y, L" T1 l5 r6 s
配置说明:
; N0 p# p1 Y5 H( I' v+ R0:睡眠模式
+ M, V4 Q' ^3 ~; F1:深度睡眠模式3 r. r O0 `3 K/ X/ q
* x+ j' |2 w- u! N: i3 E
1.2.2 模式
" u/ I+ L1 `% J8 C% t: A$ D地址匹配模式
+ i! ^; n$ z) @; }检测起始位
8 ^ J5 _, b1 y& @# z# vRXNE/RXFNE中断模式
' M- r3 [( B$ ]8 ?6 q
) r5 F+ Q _* X$ C! E二、用法
$ R; c3 S9 D$ v/ _. [0 u1 W: ?; P2.1 地址匹配模式8 k+ N* k+ w( ?! p
地址配置成0x29(0010 1001),串口需要发送0xa9来唤醒,唤醒后需要关闭唤醒中断使能,重新初始化时钟。 u# N# ~8 V+ T* @4 f# @" ?
3 Q4 N1 v' h1 s- ?4 G5 z& w0 F. d9 R. {" L
- /* make sure that no LPUART transfer is on-going */. ~6 k0 H, j$ b& j
- while (__HAL_UART_GET_FLAG(&hlpuart1, USART_ISR_BUSY) == SET);+ s+ f* F7 {/ m: K- k
- 9 X8 j1 F5 |: V, m0 |8 V0 M" h
- /* make sure that LPUART is ready to receive
! ]5 l2 r; @: p4 V! t* K( Z$ A - * (test carried out again later in HAL_UARTEx_StopModeWakeUpSourceConfig) */8 M: {1 B; r. Z
- while (__HAL_UART_GET_FLAG(&hlpuart1, USART_ISR_REACK) == RESET);! _7 a+ E% i! p% b$ J, D% L; X
7 }2 ^9 \) b5 p, ~- /* set the wake-up event:
7 f/ L; G% N0 E5 D: W - * specify address-to-match type.! ^. S7 Q3 O( X/ e) Q1 A
- * The address is 0x29, meaning the character triggering the) k% l# K6 e4 |$ D, C
- * address match is 0xA9 */
& z: b4 k& f8 q* e% z ^7 e* k - WakeUpSelection.WakeUpEvent = UART_WAKEUP_ON_ADDRESS;% f* a# [, R& Q! G. u. C2 f0 z
- WakeUpSelection.AddressLength = UART_ADDRESS_DETECT_7B;
. j$ q" }& ]5 D! [, L$ L - WakeUpSelection.Address = 0x29;
/ P8 C4 s9 M8 I8 R( C+ Q - if (HAL_UARTEx_StopModeWakeUpSourceConfig(&hlpuart1, WakeUpSelection) != HAL_OK); X1 v& \" U( X0 X9 p% a4 A" o* O" n
- {
1 `: m0 b# k. `: p - Error_Handler();
# I& O( L) Q2 H" _+ u - }( e4 E" V- e7 a# a' y# F
' T+ u+ D; L' |4 Y3 i9 Q" k% z$ `- /* Enable the LPUART Wake UP from stop mode Interrupt */- ^5 J: b4 B& T C' K9 O. f2 b
- __HAL_UART_ENABLE_IT(&hlpuart1, UART_IT_WUF);
! C: o9 Q! w" [7 G$ ] - 3 k7 \6 J* @1 y o s+ g
- /* about to enter stop mode: switch off LED1 */) I; H* H: M0 i8 v) c
- BSP_LED_Off(LED1);8 A& Y) |* |, g) x( K) O7 \
- /* enable MCU wake-up by LPUART */
" m& ~" t& \+ f$ ^ h - HAL_UARTEx_EnableStopMode(&hlpuart1);# d. a5 Q- i- [ }$ z. {0 Y' @
- /* enter STOP mode */
0 {+ C- B( p, _8 H& o& Q( R - HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI);
+ t9 h. C& B# Q1 ^8 }
5 \7 _$ p( C- `5 ?/ O1 ^3 A& O2 T- /* ... STOP mode ... */
. b" j$ I8 \8 Y0 J# m+ ]( T6 B. X
( E7 j+ W8 x! G, a, y- ]- : p' Z5 A7 T, B* b4 i# S
- /* at that point, MCU has been awoken: LED1 has been turned back on */* |, W: ?6 F/ L9 w4 _6 E
- SystemClock_Config_fromSTOP();! {7 Q- T- _- X! K$ z4 E3 }7 ?
) e; A1 x3 y4 W* j* O- /* Wake Up on 7-bit address detection successful */
1 c. R0 K2 m# a. i+ F% o - HAL_UARTEx_DisableStopMode(&hlpuart1);
复制代码
( _1 H% a! w. K2 e& T2.2 起始位模式
0 a# n) W, M* E1 t串口上产生一个起始位可以唤醒。
: A( b* |* X( T3 _0 W+ R& X7 C, |
) S" v2 D6 S. z1 F: _1 [. K; k- /* make sure that no LPUART transfer is on-going */- M$ v5 m0 q- d
- while (__HAL_UART_GET_FLAG(&hlpuart1, USART_ISR_BUSY) == SET);
8 h0 ]* d8 {& v; s
9 o0 p2 a" n4 \$ r5 x) B& |- /* make sure that LPUART is ready to receive9 _5 }0 b: u2 G+ N4 @+ F
- * (test carried out again later in HAL_UARTEx_StopModeWakeUpSourceConfig) */
; U) U3 L1 }* k+ i - while (__HAL_UART_GET_FLAG(&hlpuart1, USART_ISR_REACK) == RESET);
; r w) h5 [3 P8 ^! J/ g: D - * h' U D6 f/ @/ _6 a" H3 e
- /* set the wake-up event:% O7 q( Y. j0 s* E
- * specify wake-up on start-bit detection */' d0 z* z, ~ y) s
- WakeUpSelection.WakeUpEvent = UART_WAKEUP_ON_STARTBIT;
; B( U- `" {( w9 d - if (HAL_UARTEx_StopModeWakeUpSourceConfig(&hlpuart1, WakeUpSelection) != HAL_OK)
& W! y+ d& R g/ g6 G+ Y8 P( } - {
" u3 _: q/ K7 _( H" L. u* U. H) @ - Error_Handler();
* e! ]6 b6 y- K! D - }4 R5 t7 y. x& Y5 M- g
- + P% y5 n& K+ r( n" |, A
- /* Enable the LPUART Wake UP from STOP mode Interrupt */
+ G J0 U& B. t7 n' s4 b/ V - __HAL_UART_ENABLE_IT(&hlpuart1, UART_IT_WUF);0 m' |8 r! s) ~5 E" D
( j; `4 k4 N4 K) S- /* about to enter STOP mode: switch off LED1 */
$ y) _! i8 M7 A x/ x - BSP_LED_Off(LED1);- M$ F, O' h. ^, L& m
- /* enable MCU wake-up by LPUART */! |& c9 c6 @/ s5 F' ~7 F1 }9 p" I ]
- HAL_UARTEx_EnableStopMode(&hlpuart1);
& ]- n8 `( N" J4 o4 d* G - /* enter STOP mode */
* B) B8 y2 W9 l# T& P- \: @- `- i, K - HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI);
% ]+ D8 Q9 W v7 G4 F
. V; e+ m8 g! D- /* ... STOP mode ... */
+ z5 |. d5 i% |9 o w - ' E. g1 \0 i' {7 j/ n8 r6 q
- 3 \* b! K7 t" ]
- /* at that point, MCU has been awoken: LED1 has been turned back on */) P5 k* B1 Z: r# x- G
- SystemClock_Config_fromSTOP();
& O4 Z* {4 I& y
& `- `0 \$ x# _* i- /* Wake Up on start bit detection successful */! G! }# q$ l' f) R, c5 V1 M; `
- HAL_UARTEx_DisableStopMode(&hlpuart1);
复制代码
, L7 G& `+ X' F+ l2.3 RXNE/RXFNE中断模式
. Q8 C3 F) n" V& F+ x7 b R) c接收到一个字符可以唤醒,接收的字节是完整的。& S( j9 L- e7 u: f8 `
7 A/ z5 z) g0 d, M- /* make sure that no LPUART transfer is on-going */0 x6 P8 i5 {9 O6 K( t
- while (__HAL_UART_GET_FLAG(&hlpuart1, USART_ISR_BUSY) == SET);' [5 C) N; D J& i7 K6 P% k& a
- /* make sure that LPUART is ready to receive
2 h) }- X% v! S6 A" H: } - * (test carried out again later in HAL_UARTEx_StopModeWakeUpSourceConfig) */
( u5 b5 |7 j2 D* ]0 f - while (__HAL_UART_GET_FLAG(&hlpuart1, USART_ISR_REACK) == RESET);
' e9 }2 m- Q) r! y& ^7 d* `: `
8 ~$ ^- b; m) w+ U A4 G+ W" z6 F( P- /* set the wake-up event:& B) U# q5 B4 x: I% o
- * specify wake-up on RXNE flag */
1 h) r( W+ I% E; {; o - WakeUpSelection.WakeUpEvent = UART_WAKEUP_ON_READDATA_NONEMPTY;
/ C( s- u$ ?/ {4 I - if (HAL_UARTEx_StopModeWakeUpSourceConfig(&hlpuart1, WakeUpSelection) != HAL_OK)
: _% ?3 k' c% X9 T5 U: k - {3 @6 ^# E% N9 B" Y9 B
- Error_Handler();
1 } p% l' I6 N- Q+ }8 X - }4 C8 Z, e5 Y- M B; d& [0 e
- + A: O: l9 Q" r# ?" L3 N1 ~
- /* Enable the UART Wake UP from STOP mode Interrupt */
/ H! j# f8 v$ s4 ^8 b- s - __HAL_UART_ENABLE_IT(&hlpuart1, UART_IT_WUF);
+ P) j, f4 C3 |" E
h4 E# @+ O1 H( K) A- /* about to enter STOP mode: switch off LED1 */
8 U- S8 z) d9 m1 D C; p# { - BSP_LED_Off(LED1);: W' j8 R: o/ |5 ?% a
- /* enable MCU wake-up by LPUART */
% T" w; M- v. A% P8 p* N1 U' f - HAL_UARTEx_EnableStopMode(&hlpuart1);
m3 @6 Q8 P4 f8 H - /* enter STOP mode */
/ \) T/ s M% ?4 V0 y* g - HAL_PWR_EnterSTOPMode(PWR_LOWPOWERREGULATOR_ON, PWR_STOPENTRY_WFI);
+ l3 c6 k+ Q, M; t" r
$ `: E* _, O1 I' @: D) _; A- /* ... STOP mode ... */
5 U) k8 `' v' I+ G2 p+ X, E
5 W+ h/ _; H+ |& {' b1 v- , |) C* Z0 y7 n+ i2 u* c& p" g1 ?
- /* at that point, MCU has been awoken: LED1 has been turned back on */
: W, b: q- `( _, _) g - SystemClock_Config_fromSTOP();
) s$ ]% f1 z! N - , H; }0 ]# u8 ~& k9 Y6 h
- /* Wake Up based on RXNE flag successful */2 Z2 V: T9 t! t/ B& J, I* O
- HAL_UARTEx_DisableStopMode(&hlpuart1);
复制代码
0 q1 }+ K5 A$ j( k- J. F: \三、注意事项
1 D) \: q) r& l' Q9 p* b m如果使用地址匹配模式,需要关闭RXNE的中断。* ]1 _$ |! X8 z" `
- 5 A) T% `# f9 w! u" r. w
- __HAL_UART_DISABLE_IT(&huart1,UART_IT_RXNE);
复制代码
& N, M5 V7 o; `5 E, r+ x
3 i- u, T# ~8 a" l8 t
! g/ l) f- q7 [; }* { |