[ion] Add a console facility

Change-Id: I34b406ae8589fdd2a5d6b826b34ac411359b58dc

ion/src/device/console.cpp

@@ -0,0 +1,98 @@
+#include <ion.h>
+#include "console.h"
+
+/* This file implements a serial console.
+ * We use a 9600 8N1 serial port */
+
+namespace Ion {
+namespace Console {
+
+void writeLine(const char * line) {
+  while (*line != NULL) {
+    Device::sendChar(*line++);
+  }
+  Device::sendChar('\r');
+  Device::sendChar('\n');
+}
+
+void readLine(char * line, int maxLineLength) {
+  if (maxLineLength <= 0) {
+    return;
+  }
+  char * cursor = line;
+  char * last = line+maxLineLength-1;
+  while (true) {
+    *cursor = Device::recvChar();
+    if (*cursor == '\r' || cursor == last) {
+      *cursor = 0;
+      return;
+    }
+    cursor++;
+  }
+}
+/*
+
+  lastChar
+
+  char c = Device::recvChar();
+
+  char * lineEnd = line + maxLineLength;
+
+  while (line < lineEnd) {
+    *line++ = Device::recvChar();
+    if (*line == '\r') {
+      break;
+    }
+  }
+  *line = 0;
+}
+*/
+
+}
+}
+
+namespace Ion {
+namespace Console {
+namespace Device {
+
+void init() {
+  RCC.APB2ENR()->setUSART1EN(true);
+
+  GPIOB.MODER()->setMode(3, GPIO::MODER::Mode::AlternateFunction);
+  GPIOB.MODER()->setMode(6, GPIO::MODER::Mode::AlternateFunction);
+
+  GPIOB.AFR()->setAlternateFunction(3, GPIO::AFR::AlternateFunction::AF7);
+  GPIOB.AFR()->setAlternateFunction(6, GPIO::AFR::AlternateFunction::AF7);
+
+  UARTPort.CR1()->setUE(true);
+  UARTPort.CR1()->setTE(true);
+  UARTPort.CR1()->setRE(true);
+
+  // Set the Baud rate
+  // base clock = 16 MHz
+  // Baud rate = fAPB2/(16*USARTDIV)
+  // USARTDIV = 104.16667
+  //
+  // DIV_Fraction = 16*0.16666667
+  //  = 2.666667 -> 3
+  // DIV_Mantissa = 104 = 0x68
+  // USART_BRR = 0x683
+  UARTPort.BRR()->setDIV_FRAC(3);
+  UARTPort.BRR()->setDIV_MANTISSA(104);
+}
+
+char recvChar() {
+  while (UARTPort.SR()->getRXNE() == 0) {
+  }
+  return (char)UARTPort.DR()->get();
+}
+
+void sendChar(char c) {
+  while (UARTPort.SR()->getTXE() == 0) {
+  }
+  UARTPort.DR()->set(c);
+}
+
+}
+}
+}