Merge pull request #938 from cheyao/tkey

Add Tkey captive touch example for v203

Author: cnlohr

examples_v20x/cap_touch_tkey/Makefile

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+all : flash
+
+TARGET:= cap_touch_tkey
+TARGET_MCU:= CH32V203
+TARGET_MCU_PACKAGE:= CH32V203F8
+include ../../ch32fun/ch32fun.mk
+
+flash : cv_flash
+clean : cv_clean

examples_v20x/cap_touch_tkey/README.md

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+# Captive Touch using Tkey peripheral
+
+This example shows how to use the Tkey peripheral to sample captive buttons.
+
+It assumes that there are leds on pins PA4 and PB11, and 4 touch pads on PB1, PB0, PA7 and PA5. (This was made for my [comu](https://github.com/cheyao/comu) pcb, for pad size reference)
+
+It turns on the left led when PB1 touched, off when PB0 touched. Same for right led and PA7 and PA5.
+
+----
+
+The Tkey peripheral returns a value between 0 and 4096. On my board when pressed the value drops from ~4096 to ~1000, but this is probably dependant on pad size.
+
+You can also adjust the charge time and sampling delay with the IDATAR1 and RDATAR registers.

examples_v20x/cap_touch_tkey/cap_touch_tkey.c

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+#include "ch32fun.h"
+
+// 4096 = max
+// <1024 = pressed
+// -> 2560 = threshold
+#define THRESHOLD 2560
+
+// Captive keys (left to right):
+// A9 (PB1)
+// A8 (PB0)
+// A7 (PA7)
+// A5 (PA5)
+#define KEY_L1 9
+#define KEY_L2 8
+#define KEY_R2 7
+#define KEY_R1 5
+
+// Our clock runs at 8*18=144MHz
+// PB1 CLK is 72MHz, PB2 is 144MHz
+uint16_t sample_touch( const uint8_t key )
+{
+	// Select converted channel
+	ADC1->RSQR3 = key;
+
+	TKey1->IDATAR1 = 0x10; // CHGOFFSET
+	TKey1->RDATAR = 0x8; // ACT_DCG (How long delay to sample)
+	while ( !( ADC1->STATR & ADC_FLAG_EOC ) );
+
+	return TKey1->RDATAR;
+}
+
+int main()
+{
+	SystemInit();
+
+	// We dont use funGpioInitAll() as we also want to init ADC1
+	RCC->APB2PCENR |= ( RCC_APB2Periph_AFIO | RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOD |
+						RCC_APB2Periph_ADC1 );
+	RCC->CFGR0 |= ( 0b11 << 14 ); // Max 14MHz. PCLK2 is 144Mhz by default so /8
+
+	// PA4 is left led, PB11 is right
+	funPinMode( PA4, GPIO_Speed_10MHz | GPIO_CNF_OUT_PP );
+	funPinMode( PB11, GPIO_Speed_10MHz | GPIO_CNF_OUT_PP );
+
+	// Tkeys
+	funPinMode( PB1, GPIO_CFGLR_IN_ANALOG );
+	funPinMode( PB0, GPIO_CFGLR_IN_ANALOG );
+	funPinMode( PA5, GPIO_CFGLR_IN_ANALOG );
+	funPinMode( PA7, GPIO_CFGLR_IN_ANALOG );
+
+	// Reset ADC
+	RCC->APB2PRSTR |= RCC_APB2Periph_ADC1;
+	RCC->APB2PRSTR &= ~RCC_APB2Periph_ADC1;
+
+	// Configure sampling times for channels
+	TKey1->SAMPTR2 = ( ADC_SampleTime_7Cycles5 << ( 3 * KEY_L1 ) ) | ( ADC_SampleTime_7Cycles5 << ( 3 * KEY_L2 ) ) |
+	                 ( ADC_SampleTime_7Cycles5 << ( 3 * KEY_R2 ) ) | ( ADC_SampleTime_7Cycles5 << ( 3 * KEY_R1 ) );
+
+	// Always one channel at a time
+	ADC1->RSQR1 = ( 0 << 20 );
+	ADC1->RSQR2 = 0;
+	ADC1->CTLR2 |= ADC_ADON;
+
+	// The ADC calibration isn't really needed
+	// But we include it just in case
+
+	// Reset calibration
+	ADC1->CTLR2 |= ADC_RSTCAL;
+	while ( ADC1->CTLR2 & ADC_RSTCAL );
+
+	// Calibrate
+	ADC1->CTLR2 |= ADC_CAL;
+	while ( ADC1->CTLR2 & ADC_CAL );
+
+	TKey1->CTLR1 |= ADC_BUFEN | ( 1 << 24 ); // Enable TKey
+	while ( 1 )
+	{
+		// Left pressed
+		if ( sample_touch( KEY_L1 ) < THRESHOLD )
+		{
+			funDigitalWrite( PB11, FUN_LOW );
+		}
+		if ( sample_touch( KEY_L2 ) < THRESHOLD )
+		{
+			funDigitalWrite( PB11, FUN_HIGH );
+		}
+
+		// Right pressed
+		if ( sample_touch( KEY_R1 ) < THRESHOLD )
+		{
+			funDigitalWrite( PA4, FUN_LOW );
+		}
+		if ( sample_touch( KEY_R2 ) < THRESHOLD )
+		{
+			funDigitalWrite( PA4, FUN_HIGH );
+		}
+
+		Delay_Ms( 10 );
+	}
+}

examples_v20x/cap_touch_tkey/funconfig.h

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+#ifndef _FUNCONFIG_H
+#define _FUNCONFIG_H
+
+#endif