From 85863e31ef2effd6c310b5fdfaeea01aa4960401 Mon Sep 17 00:00:00 2001
From: cnlohr <lohr85@gmail.com>
Date: Thu, 14 Sep 2023 06:49:57 -0400
Subject: [PATCH] Let there be a "safe" version of the touch functions that
don't blow up the whole port.
---
extralibs/ch32v003_touch.h | 60 ++++++++++++++++++++++++++++++++++++--
1 file changed, 57 insertions(+), 3 deletions(-)
diff --git a/extralibs/ch32v003_touch.h b/extralibs/ch32v003_touch.h
index b0c3e90..88756af 100644
--- a/extralibs/ch32v003_touch.h
+++ b/extralibs/ch32v003_touch.h
@@ -78,9 +78,9 @@ uint32_t ReadTouchPin( GPIO_TypeDef * io, int portpin, int adcno, int iterations
#if TOUCH_FLAT == 1
-#define RELEASEIO io->OUTDR = 1<<(portpin+16*TOUCH_SLOPE); io->CFGLR = CFGFLOAT;
+#define RELEASEIO io->BSHR = 1<<(portpin+16*TOUCH_SLOPE); io->CFGLR = CFGFLOAT;
#else
-#define RELEASEIO io->CFGLR = CFGFLOAT; io->OUTDR = 1<<(portpin+16*TOUCH_SLOPE);
+#define RELEASEIO io->CFGLR = CFGFLOAT; io->BSHR = 1<<(portpin+16*TOUCH_SLOPE);
#endif
#define INNER_LOOP( n ) \
@@ -101,7 +101,7 @@ uint32_t ReadTouchPin( GPIO_TypeDef * io, int portpin, int adcno, int iterations
__enable_irq(); \
while(!(ADC1->STATR & ADC_EOC)); \
io->CFGLR = CFGDRIVE; \
- io->OUTDR = 1<<(portpin+(16*(1-TOUCH_SLOPE))); \
+ io->BSHR = 1<<(portpin+(16*(1-TOUCH_SLOPE))); \
ret += ADC1->RDATAR; \
}
@@ -119,6 +119,60 @@ uint32_t ReadTouchPin( GPIO_TypeDef * io, int portpin, int adcno, int iterations
return ret;
}
+// Run from RAM to get even more stable timing.
+// This function call takes about 8.1uS to execute.
+static uint32_t ReadTouchPinSafe( GPIO_TypeDef * io, int portpin, int adcno, int iterations ) __attribute__((noinline, section(".srodata")));
+uint32_t ReadTouchPinSafe( GPIO_TypeDef * io, int portpin, int adcno, int iterations )
+{
+ uint32_t ret = 0;
+
+ ADC1->RSQR3 = adcno;
+ ADC1->SAMPTR2 = TOUCH_ADC_SAMPLE_TIME<<(3*adcno);
+
+ // If we run multiple times with slightly different wait times, we can
+ // reduce the impact of the ADC's DNL.
+
+#define INNER_LOOP_SAFE( n ) \
+ { \
+ /* Only lock IRQ for a very narrow window. */ \
+ __disable_irq(); \
+ \
+ \
+ /* Tricky - we start the ADC BEFORE we transition the pin. By doing \
+ this We are catching it onthe slope much more effectively. */ \
+ ADC1->CTLR2 = ADC_SWSTART | ADC_ADON | ADC_EXTSEL; \
+ \
+ ADD_N_NOPS( n ) \
+ \
+ io->CFGLR = ((GPIO_CFGLR_IN_PUPD)<<(4*portpin)) | (io->CFGLR & (~(0xf<<(4*portpin)))); \
+ io->BSHR = 1<<(portpin+16*TOUCH_SLOPE); \
+ \
+ /* Sampling actually starts here, somewhere, so we can let other \
+ interrupts run */ \
+ __enable_irq(); \
+ while(!(ADC1->STATR & ADC_EOC)); \
+ __disable_irq(); \
+ io->CFGLR = (GPIO_CFGLR_OUT_2Mhz_PP)<<(4*portpin) | (io->CFGLR & (~(0xf<<(4*portpin)))); \
+ __enable_irq(); \
+ io->BSHR = 1<<(portpin+(16*(1-TOUCH_SLOPE))); \
+ ret += ADC1->RDATAR; \
+ }
+
+ int i;
+ for( i = 0; i < iterations; i++ )
+ {
+ // Wait a variable amount of time based on loop iteration, in order
+ // to get a variety of RC points and minimize DNL.
+
+ INNER_LOOP_SAFE( 0 );
+ INNER_LOOP_SAFE( 2 );
+ INNER_LOOP_SAFE( 4 );
+ }
+
+ return ret;
+}
+
+
#endif
/*
--
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