From 515cede0c78915a21bc976bd6b7f8a814b3e52c1 Mon Sep 17 00:00:00 2001
From: Jannis Konrad <kabel42@gmail.com>
Date: Sat, 20 May 2023 16:03:49 +0200
Subject: [PATCH] expand and cleanup example
---
examples/struct_gpio/struct_gpio.c | 34 +++++++++++++++++++-----------
1 file changed, 22 insertions(+), 12 deletions(-)
diff --git a/examples/struct_gpio/struct_gpio.c b/examples/struct_gpio/struct_gpio.c
index cbad5c1..978dac2 100644
--- a/examples/struct_gpio/struct_gpio.c
+++ b/examples/struct_gpio/struct_gpio.c
@@ -17,7 +17,12 @@ int main()
// Enable GPIOs
RCC->APB2PCENR |= RCC_APB2Periph_GPIOD | RCC_APB2Periph_GPIOC;
- // GPIO D0, D4 Push-Pull
+ Delay_Ms( 100 );
+
+ // all floating inputs before
+ printf("CFGLR: %lX\n", GPIOD->CFGLR); // -> CFGLR: 44444444
+
+ // GPIO D0, D4 Push-Pull, D1/SWIO floating, default analog input
GPIOD->CFGLR_bits = (struct CFGLR_t) {
.MODE0 = GPIO_CFGLR_MODE_OUT_10MHz,
.CNF0 = GPIO_CFGLR_CNF_OUT_PP,
@@ -27,31 +32,36 @@ int main()
.CNF4 = GPIO_CFGLR_CNF_OUT_PP,
};
- // GPIO C0 Push-Pull
- GPIOC->CFGLR_bits = (struct CFGLR_t) {
- .MODE0 = GPIO_CFGLR_MODE_OUT_10MHz,
- .CNF0 = GPIO_CFGLR_CNF_OUT_PP,
- };
+ // all unconfigured pins are not 0b0000, aka analog inputs with TTL Schmitttrigger disabled
+ printf("CFGLR: %lX\n", GPIOD->CFGLR); // -> CFGLR: 10041
+
+ // GPIO C0 Push-Pull with 2 volatile writes
+ GPIOC->CFGLR_bits.MODE0 = GPIO_CFGLR_MODE_OUT_10MHz;
+ GPIOC->CFGLR_bits.CNF0 = GPIO_CFGLR_CNF_OUT_PP;
+
+ // read modify write
+ struct CFGLR_t ioc = GPIOC->CFGLR_bits;
+ ioc.MODE1 = GPIO_CFGLR_MODE_IN; // not volatile
+ ioc.CNF1 = GPIO_CNF_IN_ANALOG; // not volatile
+ GPIOC->CFGLR_bits = ioc; // this should be one volatile write
while(1)
{
- // Turn on GPIOs, set in BSHR
+ // Turn D0 on and D4 off at the same time
GPIOD->BSHR_bits = (struct BSHR_t) {
.BS0 = 1,
- .BS4 = 1,
+ .BR4 = 1,
};
GPIOC->BSHR_bits.BS0 = 1;
- printf( "+%lu\n", count++ );
Delay_Ms( 100 );
- // Turn off GPIODs, clear in BSHR
+ // Turn D0 off and D4 on at the same time
GPIOD->BSHR_bits = (struct BSHR_t) {
.BR0 = 1,
- .BR4 = 1,
+ .BS4 = 1,
};
// or clear in BCR
GPIOC->BCR_bits.BR0 = 1;
- printf( "-%lu\n", count++ );
Delay_Ms( 100 );
}
}
--
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