Add UsartDriver (TX-only)

firmware/Bsp/Drivers/UsartDriver.cpp

@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2019  Max Regan
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "Bsp/Drivers/UsartDriver.h"
+#include "Bsp/macros.h"
+
+namespace BSP {
+
+using RC = BSP::ReturnCode;
+using BSP::Schedule::TaskScheduler;
+using BSP::Schedule::NextTime;
+using BSP::Time;
+
+UsartDriver::UsartDriver(USART_TypeDef *usart, TaskScheduler &scheduler)
+    : m_scheduler(scheduler)
+    , m_usart(usart)
+{}
+
+void UsartDriver::init()
+{
+    // TODO: This is all hardcoded for USART1 (doesn't exist on STM32L031)
+
+#if defined(STM32L0XX)
+    if (m_usart == USART2) {
+        RCC->APB1ENR |= RCC_APB1ENR_USART2EN;
+    }
+#elif defined(STM32L4XX)
+    if (m_usart == USART1) {
+        RCC->APB2ENR |= RCC_APB2ENR_USART1EN;
+    } else if (m_usart == USART2) {
+        RCC->APB1ENR1 |= RCC_APB1ENR1_USART2EN;
+    } else if (m_usart == USART3) {
+        RCC->APB1ENR1 |= RCC_APB1ENR1_USART3EN;
+    }
+#else
+#error "Unknown device family"
+#endif
+
+
+    // Set  TX (PA9) to output, push/pull
+    SET_TO(GPIOA->AFR[1], GPIO_AFRH_AFSEL9, 7u << GPIO_AFRH_AFSEL9_Pos); //AF7 (USART1_TX)
+    SET_TO(GPIOA->MODER, GPIO_MODER_MODE9, 2u << GPIO_MODER_MODE9_Pos); // Alternate Function
+    GPIOA->OTYPER &= ~GPIO_OTYPER_OT_9; // push/pull
+    GPIOA->PUPDR &= ~GPIO_PUPDR_PUPD9; // no pullup, no pulldown
+
+    m_usart->BRR  = (4100000) /115200L; // set baudrate (APBCLK / baud)
+    m_usart->CR1 |= (USART_CR1_RE | USART_CR1_TE); // RX, TX enable
+    m_usart->CR1 |= USART_CR1_UE; // USART enable
+}
+
+NextTime UsartDriver::execute()
+{
+    return NextTime::never();
+}
+
+RC UsartDriver::tx_blocking(const uint8_t *data, size_t len)
+{
+    for (size_t i = 0; i < len; i++) {
+        while (!(m_usart->ISR & USART_ISR_TXE)) {}
+        m_usart->TDR = data[i];
+    }
+
+    return RC::OK;
+}
+
+RC UsartDriver::tx_blocking(const char *data)
+{
+    size_t len = 0;
+    while (data[len] != '\0') {
+        len++;
+    };
+
+    return tx_blocking(reinterpret_cast<const uint8_t *>(data), len);
+}
+
+
+}

firmware/Bsp/Drivers/UsartDriver.h

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2019  Max Regan
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+#include "Bsp/ReturnCode.h"
+#include "Bsp/TaskScheduler.h"
+
+#include "Mcu.h"
+
+namespace BSP {
+
+class UsartDriver : public BSP::Schedule::Task {
+
+public:
+    // TODO: Add configurability / provide a real abstraction
+    UsartDriver(USART_TypeDef *usart, BSP::Schedule::TaskScheduler &scheduler);
+
+    void init();
+    BSP::Schedule::NextTime execute() override;
+    BSP::ReturnCode tx_blocking(const uint8_t *data, size_t len);
+    BSP::ReturnCode tx_blocking(const char *data);
+
+private:
+    BSP::Schedule::TaskScheduler &m_scheduler;
+    USART_TypeDef *m_usart;
+};
+
+}