Merge pull request #235 from baoshi/master

Update standby examples and add implementation notes.

examples/standby_autowake/README.md

@@ -6,8 +6,7 @@ This example serves to show how to put the CH32V003 into its lowest power state
 
 Power consumption should be around 10uA.  
 
-The MCU only toggles the LED and prints a message, then it goes to sleep.  
-The LED staying on demonstrates that GPIO keeps its state even when the rest of the mcu is in a coma.  
+Refer to the standby_btn example for GPIO settings.
 
 Based on the groundwork of Marek M.  
 

examples/standby_autowake/standby_autowake.c

@@ -3,30 +3,56 @@
 #include "ch32v003fun.h"
 #include <stdio.h>
 
-/* somehow this ISR won't get called??
-void AWU_IRQHandler( void ) __attribute__((interrupt));
-void AWU_IRQHandler( void ) {
-	GPIOD->OUTDR ^= (1 << 4);
-}
-*/
 
 int main()
 {
 	SystemInit();
-	Delay_Ms(100);
 
-	printf("\r\n\r\nlow power example\r\n\r\n");
+	// This delay gives us some time to reprogram the device. 
+	// Otherwise if the device enters standby mode we can't 
+	// program it any more.
+	Delay_Ms(5000);
 
-	RCC->APB2PCENR |= RCC_APB2Periph_GPIOD;
-	// GPIO D4 Push-Pull
-	GPIOD->CFGLR &= ~(0xf<<(4*4));
-	GPIOD->CFGLR |= (GPIO_Speed_10MHz | GPIO_CNF_OUT_PP)<<(4*4);
-	GPIOD->OUTDR |= (1 << 4);
+	printf("\r\n\r\nlow power example\r\n\r\n");
 
-	// give the user time to open the terminal connection
-	//Delay_Ms(5000);
-	printf("5000ms wait over\r\n");
+	// Set all GPIOs to input pull up
+	RCC->APB2PCENR |= RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOD;
+	// GPIOA: Set to output
+	GPIOA->CFGLR = (GPIO_CNF_IN_PUPD<<(4*2)) |	
+				   (GPIO_CNF_IN_PUPD<<(4*1));
+	GPIOA->BSHR = GPIO_BSHR_BS2 | GPIO_BSHR_BR1;
+	GPIOC->CFGLR = (GPIO_CNF_IN_PUPD<<(4*7)) |
+				   (GPIO_CNF_IN_PUPD<<(4*6)) |
+				   (GPIO_CNF_IN_PUPD<<(4*5)) |
+				   (GPIO_CNF_IN_PUPD<<(4*4)) |
+				   (GPIO_CNF_IN_PUPD<<(4*3)) |
+				   (GPIO_CNF_IN_PUPD<<(4*2)) |
+				   (GPIO_CNF_IN_PUPD<<(4*1)) |
+				   (GPIO_CNF_IN_PUPD<<(4*0));
+	GPIOC->BSHR = GPIO_BSHR_BS7 |
+				  GPIO_BSHR_BS6 |
+				  GPIO_BSHR_BS5 |
+				  GPIO_BSHR_BS4 |
+				  GPIO_BSHR_BS3 |
+				  GPIO_BSHR_BS2 |
+				  GPIO_BSHR_BS1 |
+				  GPIO_BSHR_BS0;
+	GPIOD->CFGLR = (GPIO_CNF_IN_PUPD<<(4*7)) |
+				   (GPIO_CNF_IN_PUPD<<(4*6)) |
+				   (GPIO_CNF_IN_PUPD<<(4*5)) |
+				   (GPIO_CNF_IN_PUPD<<(4*4)) |
+				   (GPIO_CNF_IN_PUPD<<(4*3)) |
+				   (GPIO_CNF_IN_PUPD<<(4*2)) |
+				   (GPIO_CNF_IN_PUPD<<(4*0));
+	GPIOD->BSHR = GPIO_BSHR_BS7 |
+				  GPIO_BSHR_BS6 |
+				  GPIO_BSHR_BS5 |
+				  GPIO_BSHR_BS4 |
+				  GPIO_BSHR_BS3 |
+				  GPIO_BSHR_BS2 |
+				  GPIO_BSHR_BS0;
 	
+
 	// enable power interface module clock
 	RCC->APB1PCENR |= RCC_APB1Periph_PWR;
 
@@ -62,6 +88,5 @@ int main()
 		// restore clock to full speed
 		SystemInit();
 		printf("\r\nawake, %u\r\n", counter++);
-		GPIOD->OUTDR ^= (1 << 4);
 	}
 }

examples/standby_btn/README.md

 # the deepest slumber
 
+**WARNING: You MUST hard-reboot the CH32V003 to allow it to go into deep sleep. You cannot go from flashing to deep sleep without a hard power cycle.**
+
 This example serves to show how to put the CH32V003 into its lowest power state (standby) and have it wake with a button press.  
 
-Power consumption should be around 10uA.  
+Power consumption should be around 9uA.
+
+To enter 10uA standby mode you must perform these steps:
+
+1. GPIOs other than the wake up pin can be set to either input or output mode (see notes).
+2. Set GPIO(s) for wake up to input mode with appropriate pull up/down.  
+3. Enable AFIO clock and set AFIO_EXTICR to the wakeup channel.
+4. Configure EXTI event.
+5. Set PWR_CTLR_PDDS bit in PWR_CTLR (Setting PWREN in RCC_APB1PCENR is not required hum?)
+6. Set SLEEPDEEP bit in PFIC_SCTLR
+7. Call __WFE() to enter standby mode.
 
-The MCU only toggles the LED and prints a message, then it goes back to sleep.  
-The LED staying on demonstrates that GPIO keeps its state even when the rest of the mcu is in a coma.  
+Note:
+* GPIOs in output mode will retain state during standby.
+* GPIO if set to input mode must have internal or external pulling resistor. Floating input pin will cause 100uA standby current. 
+* Once CH32V003 enters standby mode, it won't respond to any SWDIO command, therefor cannot be reprogrammed. User must provide a way to have the processor stay awake for reprogramming, e.g. some delay at startup.
+* Debug circuitry will consume power. If minichlink terminal is active (including immediately after flashing), standby current will stay around 1.2mA until power cycle.
 
 Based on the groundwork of Marek M.  
 
 ## circuit
 
-Connect LED to PD4 (with resistor), connect button to GND and PD2.  
+Connect button to GND and PD2.  
 There is no debouncing but it should suffice for waking the chip.

examples/standby_btn/standby_btn.c

@@ -3,40 +3,60 @@
 #include "ch32v003fun.h"
 #include <stdio.h>
 
-void EXTI7_0_IRQHandler( void ) __attribute__((interrupt));
-void EXTI7_0_IRQHandler( void ) {
-	//GPIOD->OUTDR ^= (1 << 4);
-}
-
-
 
 int main()
 {
 	SystemInit();
-	Delay_Ms(100);
+	
+	// This delay gives us some time to reprogram the device. 
+	// Otherwise if the device enters standby mode we can't 
+	// program it any more.
+	Delay_Ms(5000);
 
 	printf("\n\nlow power example\n\n");
+	RCC->APB2PCENR |= RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOD;
+	// GPIOA: Set to output
+	GPIOA->CFGLR = ((GPIO_CNF_OUT_PP | GPIO_Speed_2MHz)<<(4*2)) |
+				   ((GPIO_CNF_OUT_PP | GPIO_Speed_2MHz)<<(4*1));
+	GPIOA->BSHR = GPIO_BSHR_BS2 | GPIO_BSHR_BR1;
+	// GPIOC: Set to input with mixed pull-up / pull-down
+	GPIOC->CFGLR = (GPIO_CNF_IN_PUPD<<(4*7)) |
+				   (GPIO_CNF_IN_PUPD<<(4*6)) |
+				   (GPIO_CNF_IN_PUPD<<(4*5)) |
+				   (GPIO_CNF_IN_PUPD<<(4*4)) |
+				   (GPIO_CNF_IN_PUPD<<(4*3)) |
+				   (GPIO_CNF_IN_PUPD<<(4*2)) |
+				   (GPIO_CNF_IN_PUPD<<(4*1)) |
+				   (GPIO_CNF_IN_PUPD<<(4*0));
+	GPIOC->BSHR = GPIO_BSHR_BS7 |
+				  GPIO_BSHR_BR6 |
+				  GPIO_BSHR_BS5 |
+				  GPIO_BSHR_BR4 |
+				  GPIO_BSHR_BS3 |
+				  GPIO_BSHR_BR2 |
+				  GPIO_BSHR_BS1 |
+				  GPIO_BSHR_BR0;
+	// GPIOD: D2 set to input pull-up
+	GPIOD->CFGLR = (GPIO_CNF_IN_PUPD<<(4*7)) |
+				   (GPIO_CNF_IN_PUPD<<(4*6)) |
+				   (GPIO_CNF_IN_PUPD<<(4*5)) |
+				   (GPIO_CNF_IN_PUPD<<(4*4)) |
+				   (GPIO_CNF_IN_PUPD<<(4*3)) |
+				   (GPIO_CNF_IN_PUPD<<(4*2)) |
+				   (GPIO_CNF_IN_PUPD<<(4*0));
+	GPIOD->BSHR = GPIO_BSHR_BR7 |
+				  GPIO_BSHR_BS6 |
+				  GPIO_BSHR_BR5 |
+				  GPIO_BSHR_BS4 |
+				  GPIO_BSHR_BR3 |
+				  GPIO_BSHR_BS2 |
+				  GPIO_BSHR_BR0;
 
-	RCC->APB2PCENR |= RCC_APB2Periph_GPIOD;
-	// GPIO D4 Push-Pull
-	GPIOD->CFGLR &= ~(0xf<<(4*4));
-	GPIOD->CFGLR |= (GPIO_Speed_10MHz | GPIO_CNF_OUT_PP)<<(4*4);
-	GPIOD->OUTDR |= (1 << 4);
-
-	// give the user time to open the terminal connection
-	//Delay_Ms(5000);
-	//printf("5000ms wait over\r\n");
-	
-	// enable alternate IO function module clock
+	// AFIO is needed for EXTI
 	RCC->APB2PCENR |= RCC_AFIOEN;
 
-	// configure button on PD2 as input, pullup
-	GPIOD->CFGLR &= ~(0xf<<(2*4));
-	GPIOD->CFGLR |= (GPIO_CNF_IN_PUPD)<<(2*4);
-	GPIOD->BSHR = (1 << 2);
-
 	// assign pin 2 interrupt from portD (0b11) to EXTI channel 2
-	AFIO->EXTICR |= (uint32_t)(0b11 << (2 * 2));
+	AFIO->EXTICR |= (uint32_t)(0b11 << (2*2));
 
 	// enable line2 interrupt event
 	EXTI->EVENR |= EXTI_Line2;
@@ -56,6 +76,6 @@ int main()
 		// restore clock to full speed
 		SystemInit();
 		printf("\nawake, %u\n", counter++);
-		GPIOD->OUTDR ^= (1 << 4);
+		Delay_Ms(5000);	// wake and reflash can happen here
 	}
 }