Merge pull request #100 from dwillmore/master

Add hsitrim example

examples/hsitrim/Makefile

+all : flash
+
+TARGET:=hsitrim
+
+CFLAGS+=-DTINYVECTOR -DSTDOUT_UART
+
+include ../../ch32v003fun/ch32v003fun.mk
+
+flash : cv_flash
+clean : cv_clean
+

examples/hsitrim/hsitrim.c

+#define SYSTEM_CORE_CLOCK 48000000
+#define APB_CLOCK SYSTEM_CORE_CLOCK
+
+#include "ch32v003fun.h"
+#include <stdio.h>
+
+void set_trim(uint32_t trim)
+{
+	uint32_t regtemp;
+
+	regtemp = RCC->CTLR & ~RCC_HSITRIM;
+	regtemp |= trim<<3;
+	RCC->CTLR = regtemp;
+}
+
+
+int main()
+{
+	uint32_t trim, regtemp;
+	uint8_t key;
+
+	SystemInit48HSI();
+        SetupUART( UART_BRR );
+//        SetupDebugPrintf();
+
+	Delay_Ms(50);
+	printf("\r\r\n\nHSITRIM example.\r\n");
+
+	regtemp = RCC->CTLR;
+	printf("RCC->CTLR: 0x%08lX : ", regtemp);
+	if (regtemp & RCC_PLLRDY) printf("RCC_PLLRDY ");
+	if (regtemp & RCC_PLLON)  printf("RCC_PLLON ");
+	if (regtemp & RCC_CSSON)  printf("RCC_CSSON ");
+	if (regtemp & RCC_HSEBYP) printf("RCC_HSEBYP ");
+	if (regtemp & RCC_HSERDY) printf("RCC_HSERDY ");
+	if (regtemp & RCC_HSEON)  printf("RCC_HSEON ");
+	if (regtemp & RCC_HSIRDY) printf("RCC_HSIRDY ");
+	if (regtemp & RCC_HSION)  printf("RCC_HSION ");
+	printf("\r\n");
+	printf("HSICAL: 0x%02lX\r\n", (regtemp & RCC_HSICAL) >> 8);
+	trim = (regtemp & RCC_HSITRIM) >> 3;
+	printf("HSITRIM: 0x%02lX\r\n", trim);
+
+	RCC->APB2PCENR |= RCC_APB2Periph_GPIOC;
+
+        // PC4 is T1CH4, 50MHz Output PP CNF = 10: Mux PP, MODE = 11: Out 50MHz
+        GPIOC->CFGLR &= ~(GPIO_CFGLR_MODE4 | GPIO_CFGLR_CNF4);
+        GPIOC->CFGLR |= GPIO_CFGLR_CNF4_1 | GPIO_CFGLR_MODE4_0 | GPIO_CFGLR_MODE4_1;
+
+	printf("Enabling HSI signal with MCO function on PC4\r\n");
+	regtemp = (RCC->CFGR0 & ~RCC_CFGR0_MCO) | RCC_CFGR0_MCO_HSI;
+	RCC->CFGR0 = regtemp;
+//	Delay_Ms(5000);
+
+	// Setup UART RX pin SetupUART() does most of the work.  ###beware### if you use DebugPrintf, this will break!
+	// Input, GPIO D6, with AutoFunction
+        GPIOD->CFGLR &= ~(0xf<<(4*6));
+        GPIOD->CFGLR |= (GPIO_CNF_IN_FLOATING)<<(4*6);
+	USART1->CTLR1 |= USART_CTLR1_RE;
+
+	printf("\r\nPress ',' to decrease HSITRIM.  Press '.' to increase HSITRIM.\r\n");
+	while(1){
+		if(USART1->STATR & USART_STATR_RXNE){
+			key = (uint8_t)USART1->DATAR;
+//			printf("Got key '%c'\r\n", key);
+			if(key == '.'){
+				if(trim < 0x1f) trim++;
+				printf("Setting HSITRIM to: 0x%02lX\r\n", trim);
+				set_trim(trim);
+			}
+			if(key == ','){
+				if(trim > 0x00) trim--;
+				printf("Setting HSITRIM to: 0x%02lX\r\n", trim);
+				set_trim(trim);
+			}
+		}
+	}
+}