Update to v086r04 release.

byuu says:

There will probably be a series of small WIPs as I experiment here.

snes/controller/serial is now snes/controller/uart. Asynchronous serial
communications, typically capped at 57,600 baud.
snes/controller/usart is new. It aims to emulate the SNES connected to
a Teensy++ board, and can easily handle 524,288 baud.
And much more importantly, it's synchronous, so there are no timing
issues anymore. Just bit-bang as fast as you can.

Right now, the USART code is just enough for SNES->PC to transfer data
to ... well, nothing yet.

Unless anyone is actually using the UART stuff, I'll be removing it once
the USART is totally up and running.
No sense maintaining code that is 10x slower, more error prone, and used
by nobody.

Note: this is all thanks to blargg being absolutely amazing.

bsnes/base/base.hpp

@@ -1,7 +1,7 @@
 #ifndef BASE_HPP
 #define BASE_HPP
 
-const char Version[] = "086.03";
+const char Version[] = "086.04";
 
 #include <nall/platform.hpp>
 #include <nall/algorithm.hpp>

bsnes/snes/controller/controller.cpp

@@ -8,7 +8,8 @@ namespace SNES {
 #include "mouse/mouse.cpp"
 #include "superscope/superscope.cpp"
 #include "justifier/justifier.cpp"
-#include "serial/serial.cpp"
+#include "uart/uart.cpp"
+#include "usart/usart.cpp"
 
 void Controller::Enter() {
   if(co_active() == input.port1->thread) input.port1->enter();

bsnes/snes/controller/controller.hpp

@@ -32,4 +32,5 @@ struct Controller : Processor {
 #include "mouse/mouse.hpp"
 #include "superscope/superscope.hpp"
 #include "justifier/justifier.hpp"
-#include "serial/serial.hpp"
+#include "uart/uart.hpp"
+#include "usart/usart.hpp"

bsnes/snes/controller/uart/uart.cpp

@@ -1,6 +1,6 @@
 #ifdef CONTROLLER_CPP
 
-//Serial communications cable emulation:
+//Asynchronous serial communications cable emulation:
 //The SNES controller ports can be used for bi-directional serial communication
 //when wired to a specialized controller. This class implements said controller,
 //for the primary purpose of testing code outside of real hardware.
@@ -30,15 +30,19 @@ static void snesserial_tick(unsigned clocks);
 static uint8 snesserial_read();
 static void snesserial_write(uint8 data);
 
-void Serial::enter() {
-  if(enable == false) while(true) step(1);  //fallback, in case library was not found
+void UART::enter() {
+  if(enable == false) {
+    //fallback, in case library was not found
+    interface->message("UART library not found");
+    while(true) step(1);
+  }
   step(256 * 8);  //simulate warm-up delay
   if(flowcontrol()) data2 = 1;
   main(snesserial_tick, snesserial_read, snesserial_write);  //stubs for Serial::step, Serial::read, Serial::write
   while(true) step(1);  //fallback, in case snesserial_main() returns (it should never do so)
 }
 
-uint8 Serial::read() {
+uint8 UART::read() {
   while(latched == 0) step(1);
   while(latched == 1) step(1);
   step(4);
@@ -52,7 +56,7 @@ uint8 Serial::read() {
   return data;
 }
 
-void Serial::write(uint8 data) {
+void UART::write(uint8 data) {
   if(flowcontrol()) while(iobit()) step(1);
   step(8);
 
@@ -69,20 +73,18 @@ void Serial::write(uint8 data) {
   step(8);
 }
 
-uint2 Serial::data() {
+uint2 UART::data() {
   return (data2 << 1) | (data1 << 0);
 }
 
-void Serial::latch(bool data) {
+void UART::latch(bool data) {
   latched = data;
 }
 
-Serial::Serial(bool port) : Controller(port) {
+UART::UART(bool port) : Controller(port) {
   enable = false;
-  string basename = interface->path(Cartridge::Slot::Base, "serial.so");
-  string name = notdir(basename);
-  string path = dir(basename);
-  if(open(name, path)) {
+  string filename = interface->path(Cartridge::Slot::Base, "uart.so");
+  if(open_absolute(filename)) {
     baudrate = sym("snesserial_baudrate");
     flowcontrol = sym("snesserial_flowcontrol");
     main = sym("snesserial_main");
@@ -95,7 +97,7 @@ Serial::Serial(bool port) : Controller(port) {
   data2 = 0;
 }
 
-Serial::~Serial() {
+UART::~UART() {
   if(opened()) close();
 }
 
@@ -103,42 +105,42 @@ Serial::~Serial() {
 
 static void snesserial_tick(unsigned clocks) {
   if(co_active() == input.port1->thread) {
-    if(dynamic_cast<Serial*>(input.port1)) {
-      return ((Serial*)input.port1)->step(clocks);
+    if(dynamic_cast<UART*>(input.port1)) {
+      return ((UART*)input.port1)->step(clocks);
     }
   }
 
   if(co_active() == input.port2->thread) {
-    if(dynamic_cast<Serial*>(input.port2)) {
-      return ((Serial*)input.port2)->step(clocks);
+    if(dynamic_cast<UART*>(input.port2)) {
+      return ((UART*)input.port2)->step(clocks);
     }
   }
 }
 
 static uint8 snesserial_read() {
   if(co_active() == input.port1->thread) {
-    if(dynamic_cast<Serial*>(input.port1)) {
-      return ((Serial*)input.port1)->read();
+    if(dynamic_cast<UART*>(input.port1)) {
+      return ((UART*)input.port1)->read();
     }
   }
 
   if(co_active() == input.port2->thread) {
-    if(dynamic_cast<Serial*>(input.port2)) {
-      return ((Serial*)input.port2)->read();
+    if(dynamic_cast<UART*>(input.port2)) {
+      return ((UART*)input.port2)->read();
     }
   }
 }
 
 static void snesserial_write(uint8 data) {
   if(co_active() == input.port1->thread) {
-    if(dynamic_cast<Serial*>(input.port1)) {
-      return ((Serial*)input.port1)->write(data);
+    if(dynamic_cast<UART*>(input.port1)) {
+      return ((UART*)input.port1)->write(data);
     }
   }
 
   if(co_active() == input.port2->thread) {
-    if(dynamic_cast<Serial*>(input.port2)) {
-      return ((Serial*)input.port2)->write(data);
+    if(dynamic_cast<UART*>(input.port2)) {
+      return ((UART*)input.port2)->write(data);
     }
   }
 }

bsnes/snes/controller/uart/uart.hpp

@@ -1,11 +1,11 @@
-struct Serial : Controller, public library {
+struct UART : Controller, public library {
   void enter();
   uint8 read();
   void write(uint8 data);
   uint2 data();
   void latch(bool data);
-  Serial(bool port);
-  ~Serial();
+  UART(bool port);
+  ~UART();
 
 private:
   bool enable;

bsnes/snes/controller/usart/usart.cpp

@@ -0,0 +1,75 @@
+#ifdef CONTROLLER_CPP
+
+//Synchronous serial communications cable emulation
+
+//Hardware:
+//Teensy++ 2.0 USB
+//AT90USB1286
+
+//Connection Diagram:
+//[SNES]  [Teensy]
+// +5v     ---
+// Clock   D5
+// Latch   D2
+// Data1   D3
+// Data2   ---
+// IOBit   ---
+// GND     GND
+
+static uint8 usart_read();
+static void usart_write(uint8 data);
+
+//USART -> SNES
+uint2 USART::data() {
+  if(rxlength == 0) {
+    data1 = 0;
+    rxdata = usart_read();
+  } else if(rxlength <= 8) {
+    data1 = rxdata & 1;
+    rxdata >>= 1;
+  } else {
+    data1 = 1;
+    rxlength = 0;
+  }
+
+  return (data2 << 1) | (data1 << 0);
+}
+
+//SNES -> USART
+void USART::latch(bool data) {
+  if(txlength == 0 && latched == 1 && data == 0) {
+    txlength++;
+  } else if(txlength <= 8) {
+    txdata = (data << 7) | (txdata >> 1);
+    txlength++;
+  } else {
+    if(data == 1) usart_write(txdata);
+    txlength = 0;
+  }
+
+  latched = data;
+}
+
+USART::USART(bool port) : Controller(port) {
+  latched = 0;
+  data1 = 0;
+  data2 = 0;
+
+  rxlength = 0;
+  rxdata = 0;
+
+  txlength = 0;
+  txdata = 0;
+}
+
+USART::~USART() {
+}
+
+static uint8 usart_read() {
+  return 0xff;
+}
+
+static void usart_write(uint8 data) {
+}
+
+#endif

bsnes/snes/controller/usart/usart.hpp

@@ -0,0 +1,17 @@
+struct USART : Controller, public library {
+  uint2 data();
+  void latch(bool data);
+  USART(bool port);
+  ~USART();
+
+private:
+  bool latched;
+  bool data1;
+  bool data2;
+
+  uint8 rxlength;
+  uint8 rxdata;
+
+  uint8 txlength;
+  uint8 txdata;
+};

bsnes/snes/system/input.cpp

@@ -17,7 +17,8 @@ void Input::connect(bool port, Input::Device id) {
   case Device::SuperScope: controller = new SuperScope(port); break;
   case Device::Justifier: controller = new Justifier(port, false); break;
   case Device::Justifiers: controller = new Justifier(port, true); break;
-  case Device::Serial: controller = new Serial(port); break;
+  case Device::UART: controller = new UART(port); break;
+  case Device::USART: controller = new USART(port); break;
   }
 
   switch(port) {

bsnes/snes/system/input.hpp

@@ -7,7 +7,8 @@ struct Input {
     SuperScope,
     Justifier,
     Justifiers,
-    Serial,
+    UART,
+    USART,
   };
 
   enum class JoypadID : unsigned {

bsnes/ui/general/main-window.cpp

@@ -49,9 +49,10 @@ MainWindow::MainWindow() {
       snesPort2Device[4].setText("Super Scope");
       snesPort2Device[5].setText("Justifier");
       snesPort2Device[6].setText("Dual Justifiers");
-      snesPort2Device[7].setText("Serial Cable");
+      snesPort2Device[7].setText("Serial UART");
+      snesPort2Device[8].setText("Serial USART");
       RadioItem::group(snesPort2Device[0], snesPort2Device[1], snesPort2Device[2], snesPort2Device[3],
-                       snesPort2Device[4], snesPort2Device[5], snesPort2Device[6], snesPort2Device[7]);
+        snesPort2Device[4], snesPort2Device[5], snesPort2Device[6], snesPort2Device[7], snesPort2Device[8]);
       snesPort2Device[config->snes.controllerPort2Device].setChecked();
     snesCartridgeUnload.setText("&Unload Cartridge");
 
@@ -138,6 +139,7 @@ MainWindow::MainWindow() {
       snesPort2.append(snesPort2Device[5]);
       snesPort2.append(snesPort2Device[6]);
       snesPort2.append(snesPort2Device[7]);
+      snesPort2.append(snesPort2Device[8]);
     snesMenu.append(snesSeparator2);
     snesMenu.append(snesCartridgeUnload);
 
@@ -255,6 +257,7 @@ MainWindow::MainWindow() {
   snesPort2Device[5].onActivate = [&] { interface->setController(1, 5); };
   snesPort2Device[6].onActivate = [&] { interface->setController(1, 6); };
   snesPort2Device[7].onActivate = [&] { interface->setController(1, 7); };
+  snesPort2Device[8].onActivate = [&] { interface->setController(1, 8); };
 
   snesCartridgeUnload.onActivate = { &Interface::unloadCartridge, interface };
 

bsnes/ui/general/main-window.hpp

@@ -31,7 +31,7 @@ struct MainWindow : Window {
     Menu snesPort1;
       RadioItem snesPort1Device[4];
     Menu snesPort2;
-      RadioItem snesPort2Device[8];
+      RadioItem snesPort2Device[9];
     Separator snesSeparator2;
     Item snesCartridgeUnload;
 

bsnes/ui/interface/snes/snes.cpp

@@ -22,7 +22,8 @@ void InterfaceSNES::setController(bool port, unsigned device) {
   case 4: return SNES::input.connect(1, SNES::Input::Device::SuperScope);
   case 5: return SNES::input.connect(1, SNES::Input::Device::Justifier);
   case 6: return SNES::input.connect(1, SNES::Input::Device::Justifiers);
-  case 7: return SNES::input.connect(1, SNES::Input::Device::Serial);
+  case 7: return SNES::input.connect(1, SNES::Input::Device::UART);
+  case 8: return SNES::input.connect(1, SNES::Input::Device::USART);
   }
 }
 
@@ -412,7 +413,8 @@ string InterfaceSNES::path(SNES::Cartridge::Slot slot, const string &hint) {
       track.trim<1>("track-", ".pcm");
       return interface->base.filename(hint, { "-", decimal(track), ".pcm" });
     }
-    if(hint == "serial.so") return { dir(interface->base.name), "libserial.so" };
+    if(hint == "uart.so") return { dir(interface->base.name), "uart.so" };
+    if(hint == "usart.so") return { dir(interface->base.name), "usart.so" };
     if(hint.endswith(".rom")) return { dir(interface->base.name), hint };
   }
   return { dir(interface->base.name), hint };