From 41fdd2b1f35bcb4224fdb8fee2b959e09d1f5916 Mon Sep 17 00:00:00 2001
From: Trygve Laugstøl <trygvis@inamo.no>
Date: Wed, 25 Jan 2017 22:22:30 +0100
Subject: o Seemingly working Mutexes. o Dropping the privileged/unprivileged
 split for now.

---
 apps/usb1/usb1.cpp | 148 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 148 insertions(+)
 create mode 100644 apps/usb1/usb1.cpp

(limited to 'apps/usb1/usb1.cpp')

diff --git a/apps/usb1/usb1.cpp b/apps/usb1/usb1.cpp
new file mode 100644
index 0000000..5b50605
--- /dev/null
+++ b/apps/usb1/usb1.cpp
@@ -0,0 +1,148 @@
+#include <stdint.h>
+#include <stm32f10x.h>
+#include <stm32f10x_rcc.h>
+#include <stm32f10x_gpio.h>
+#include <stm32f10x_usart.h>
+#include <misc.h>
+
+#include "debug.h"
+#include "tinyprintf.h"
+#include "playground.h"
+
+extern "C"
+__attribute__((naked, used))
+void HardFault_Handler_C(uint32_t *hardfault_args) {
+    dbg_printf("r0 = 0x%08lx (%lu)\n", hardfault_args[0], hardfault_args[0]);
+    dbg_printf("r1 = 0x%08lx (%lu)\n", hardfault_args[1], hardfault_args[1]);
+    dbg_printf("r2 = 0x%08lx (%lu)\n", hardfault_args[2], hardfault_args[2]);
+    dbg_printf("r3 = 0x%08lx (%lu)\n", hardfault_args[3], hardfault_args[3]);
+    dbg_printf("r12 = 0x%08lx (%lu)\n", hardfault_args[4], hardfault_args[4]);
+    dbg_printf("lr = 0x%08lx (%lu)\n", hardfault_args[5], hardfault_args[5]);
+    dbg_printf("pc = 0x%08lx (%lu)\n", hardfault_args[6], hardfault_args[6]);
+    dbg_printf("psr = 0x%08lx (%lu)\n", hardfault_args[7], hardfault_args[7]);
+    dbg_printf("\n");
+
+    Default_Handler();
+
+    halt();
+}
+
+int run = 1;
+
+volatile USART_TypeDef *usart1 = (volatile USART_TypeDef *) USART1_BASE;
+
+volatile uint8_t tx_ready = 0;
+
+/*
+ * When we get there the stack pointer is set
+ */
+int main() {
+    SystemInit();
+
+    init_printf(nullptr, dbg_putc);
+    dbg_printf("usb1\n");
+
+    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USB, ENABLE);
+
+    RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO
+                           | RCC_APB2Periph_USART1
+                           | RCC_APB2Periph_GPIOA
+                           | RCC_APB2Periph_GPIOB
+                           | RCC_APB2Periph_GPIOC, ENABLE);
+
+    /* ***************************************** */
+
+    // Debug on port B
+
+    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOB, ENABLE);
+    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOB, DISABLE);
+
+    // Make Port B's pin #5 the debug output pin
+    GPIO_InitTypeDef init;
+    GPIO_StructInit(&init);
+    init.GPIO_Pin = GPIO_Pin_5;
+    init.GPIO_Mode = GPIO_Mode_Out_PP;
+    GPIO_Init(GPIOB, &init);
+
+    /* ***************************************** */
+
+    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOA, ENABLE);
+    RCC_APB2PeriphResetCmd(RCC_APB2Periph_GPIOA, DISABLE);
+
+    /*
+     * PA9	USART1_TX
+     * PA10	USART1_RX
+     */
+
+    // Enable USART1
+    RCC_APB2PeriphResetCmd(RCC_APB2Periph_USART1, ENABLE);
+    RCC_APB2PeriphResetCmd(RCC_APB2Periph_USART1, DISABLE);
+
+    // Make the TX pin an output
+    GPIO_StructInit(&init);
+    init.GPIO_Pin = GPIO_Pin_9;
+    init.GPIO_Mode = GPIO_Mode_AF_PP;
+    GPIO_Init(GPIOA, &init);
+
+    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
+    NVIC_InitTypeDef NVIC_InitStruct = {
+        NVIC_IRQChannel: USART1_IRQn,
+        NVIC_IRQChannelPreemptionPriority: 0,
+        NVIC_IRQChannelSubPriority: 0,
+        NVIC_IRQChannelCmd: ENABLE,
+    };
+    NVIC_Init(&NVIC_InitStruct);
+    NVIC_EnableIRQ(USART1_IRQn);
+
+    // 8 bit mode
+    USART1->CR1 &= ~USART_CR1_M;
+    USART1->CR2 &= ~USART_CR2_STOP_1;
+
+    // Set baud rate
+    int mantissa = 39;
+    int fraction = static_cast<int>(16 * 0.0625); // == 1
+    // 72M / (16*39.0625) = 115200
+    USART1->BRR = static_cast<uint16_t >(mantissa << 4 | fraction);
+
+    USART1->CR1 |= USART_CR1_UE /* Set UART Enable */
+                   | USART_CR1_TE /* Set Transmission Enable */
+                   | USART_CR1_TXEIE; /* Set TX buffer Empty Interrupt Enable */
+
+    char c = 'A';
+    tx_ready = 1;
+    while (run) {
+        // wait for TX to be ready
+        while (!tx_ready);
+        tx_ready = 0;
+
+        GPIO_SetBits(GPIOB, GPIO_Pin_All);
+        GPIO_ResetBits(GPIOB, GPIO_Pin_All);
+
+        USART1->DR = (uint16_t) c;
+        USART_ITConfig(USART1, USART_IT_TXE, ENABLE);
+
+        if (c == 'Z') {
+            c = 'a';
+        } else if (c == 'z') {
+            c = '0';
+        } else if (c == '9') {
+            c = '\n';
+        } else if (c == '\n') {
+            c = 'A';
+        } else {
+            c++;
+        }
+    }
+
+    return 0;
+}
+
+extern "C"
+void USART1_IRQHandler() {
+    tx_ready = 1;
+
+    if (USART_GetITStatus(USART1, USART_IT_TXE) == SET) {
+        // Disable the interrupt
+        USART_ITConfig(USART1, USART_IT_TXE, DISABLE);
+    }
+}
-- 
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