From 5764d87a0814a78a6afbfbcba5a32fe7fd91e04b Mon Sep 17 00:00:00 2001
From: Thomas Kolb <thomas@tkolb.de>
Date: Sat, 5 Jun 2021 15:49:29 +0200
Subject: [PATCH] Added the charge pump driver

---
 src/charge_pump.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++
 src/charge_pump.h |  9 +++++++
 src/main.c        | 14 +++++++++-
 src/pinout.h      |  8 +++++-
 4 files changed, 95 insertions(+), 2 deletions(-)
 create mode 100644 src/charge_pump.c
 create mode 100644 src/charge_pump.h

diff --git a/src/charge_pump.c b/src/charge_pump.c
new file mode 100644
index 0000000..825c5d3
--- /dev/null
+++ b/src/charge_pump.c
@@ -0,0 +1,66 @@
+#include <libopencm3/stm32/gpio.h>
+#include <libopencm3/stm32/timer.h>
+
+#include "libopencm3/stm32/common/timer_common_all.h"
+#include "pinout.h"
+
+#include "charge_pump.h"
+
+
+void charge_pump_init(void)
+{
+	// set alternate function to Timer 1, channel 1 output
+	gpio_set_af(CHARGE_PUMP_PORT, GPIO_AF2, CHARGE_PUMP_DRV_PIN);
+
+	// set the GPIO to low until the charge pump is started
+	gpio_clear(CHARGE_PUMP_PORT, CHARGE_PUMP_DRV_PIN);
+	gpio_mode_setup(CHARGE_PUMP_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, CHARGE_PUMP_DRV_PIN);
+
+	// *** TIM1 ***
+	// Configure channel 1 for PWM
+	// Ch1 = charge pump output
+
+	timer_set_mode(TIM1, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
+
+	// set up PWM channel
+	timer_set_oc_mode(TIM1, TIM_OC1, TIM_OCM_PWM1);
+	timer_enable_oc_output(TIM1, TIM_OC1);
+	timer_enable_oc_preload(TIM1, TIM_OC1);
+	timer_set_oc_polarity_high(TIM1, TIM_OC1);
+
+	// prescaler
+	timer_set_prescaler(TIM1, 48 - 1); // Timer runs at 1 MHz
+
+	// auto-reload value
+	timer_set_period(TIM1, 10000 - 1); // overflow every 10000 cycles = 100 Hz
+
+	// output compare value
+	timer_set_oc_value(TIM1, TIM_OC1, 100); // High for 100 cycles = 100 μs
+
+	// only generate interrupt on overflow
+	timer_update_on_overflow(TIM1);
+
+	// enable main output
+	timer_enable_break_main_output(TIM1);
+}
+
+
+void charge_pump_start(void)
+{
+	// start the timer
+	timer_enable_counter(TIM1);
+
+	// set mode to AF to pass through the PWM signal from the timer
+	gpio_mode_setup(CHARGE_PUMP_PORT, GPIO_MODE_AF, GPIO_PUPD_NONE, CHARGE_PUMP_DRV_PIN);
+}
+
+
+void charge_pump_stop(void)
+{
+	// stop the timer
+	timer_disable_counter(TIM1);
+
+	// set the output static low
+	gpio_clear(CHARGE_PUMP_PORT, CHARGE_PUMP_DRV_PIN);
+	gpio_mode_setup(CHARGE_PUMP_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, CHARGE_PUMP_DRV_PIN);
+}
diff --git a/src/charge_pump.h b/src/charge_pump.h
new file mode 100644
index 0000000..36096c9
--- /dev/null
+++ b/src/charge_pump.h
@@ -0,0 +1,9 @@
+#ifndef CHARGE_PUMP_H
+#define CHARGE_PUMP_H
+
+void charge_pump_init(void);
+
+void charge_pump_start(void);
+void charge_pump_stop(void);
+
+#endif // CHARGE_PUMP_H
diff --git a/src/main.c b/src/main.c
index 0ead9c3..e5e29bf 100644
--- a/src/main.c
+++ b/src/main.c
@@ -15,6 +15,7 @@
 #include <fxp_basic.h>
 
 #include "led_chplex.h"
+#include "charge_pump.h"
 
 volatile int wait_frame = 1;
 
@@ -34,7 +35,13 @@ static void init_clock(void)
 	rcc_clock_setup_in_hse_8mhz_out_48mhz();    // generate 48 MHz from external 8 MHz crystal
 	//rcc_clock_setup_in_hsi_out_48mhz();         // generate ~48 MHz from internal RC oscillator
 
+	// enable TIM1 for PWM generation
+	rcc_periph_clock_enable(RCC_TIM1);
+
 	// enable GPIO clocks:
+	// Port A is needed for the charge pump, extension port and analog input
+	rcc_periph_clock_enable(RCC_GPIOA);
+
 	// Port B is needed for the LEDs
 	rcc_periph_clock_enable(RCC_GPIOB);
 }
@@ -93,10 +100,13 @@ int main(void)
 	//uint32_t cpuload = 0;
 	uint64_t timebase_ms = 0;
 	bool ledtest_done = false;
+	bool startup_done = false;
 
 	init_clock();
 	init_gpio();
 
+	charge_pump_init();
+
 	led_chplex_init();
 	led_chplex_on(LED_CHPLEX_IDX_SOLAR_ON);
 
@@ -107,11 +117,13 @@ int main(void)
 
 		if(!ledtest_done) {
 			ledtest_done = ledtest(timebase_ms);
+		} else if(!startup_done) {
+			charge_pump_start();
+			startup_done = true;
 		} else if(timebase_ms % 500 == 0) {
 			led_chplex_toggle(LED_CHPLEX_IDX_DISCHARGE_PULSE);
 		}
 
-
 		led_chplex_periodic();
 
 		timebase_ms++;
diff --git a/src/pinout.h b/src/pinout.h
index 202729b..5dfd3ce 100644
--- a/src/pinout.h
+++ b/src/pinout.h
@@ -3,7 +3,7 @@
 
 /* LEDs */
 
-#define LED_PORT             GPIOB
+#define LED_PORT         GPIOB
 
 #define LED_A_PIN        GPIO0
 #define LED_B_PIN        GPIO1
@@ -11,4 +11,10 @@
 
 #define LED_ALL_PINS     (LED_A_PIN | LED_B_PIN | LED_C_PIN)
 
+/* Charge pump */
+
+#define CHARGE_PUMP_PORT     GPIOA
+
+#define CHARGE_PUMP_DRV_PIN  GPIO8      // Timer 1, Channel 1
+
 #endif // PINOUT_H