Code:
/**
* Gamecube controller to Nintendo 64 adapter
* by Andrew Brown
* Rewritten for N64 to HID by Peter Den Hartog
*/
/**
* To use, hook up the following to the Arduino Duemilanove:
* Digital I/O 2: N64 serial line
* All appropriate grounding and power lines
*/
#include "pins_arduino.h"
#define N64_PIN 2
#define N64_PIN_DIR DDRD
// these two macros set arduino pin 2 to input or output, which with an
// external 1K pull-up resistor to the 3.3V rail, is like pulling it high or
// low. These operations translate to 1 op code, which takes 2 cycles
#define N64_HIGH DDRD &= ~0x4
#define N64_LOW DDRD |= 0x4
#define N64_QUERY (PIND & 0x4)
// 8 bytes of data that we get from the controller
struct {
// bits: 0, 0, 0, start, y, x, b, a
unsigned char data1;
// bits: 1, L, R, Z, Dup, Ddown, Dright, Dleft
unsigned char data2;
char stick_x;
char stick_y;
} N64_status;
char N64_raw_dump[33]; // 1 received bit per byte
void N64_send(unsigned char *buffer, char length);
void N64_get();
void print_N64_status();
void translate_raw_data();
#include "crc_table.h"
void setup()
{
Serial.begin(115200);
Joystick.useManualSend(true);
// Communication with gamecube controller on this pin
// Don't remove these lines, we don't want to push +5V to the controller
digitalWrite(N64_PIN, LOW);
pinMode(N64_PIN, INPUT);
// Initialize the gamecube controller by sending it a null byte.
// This is unnecessary for a standard controller, but is required for the
// Wavebird.
unsigned char initialize = 0x00;
noInterrupts();
N64_send(&initialize, 1);
// Stupid routine to wait for the gamecube controller to stop
// sending its response. We don't care what it is, but we
// can't start asking for status if it's still responding
int x;
for (x=0; x<64; x++) {
// make sure the line is idle for 64 iterations, should
// be plenty.
if (!N64_QUERY)
x = 0;
}
// Query for the gamecube controller's status. We do this
// to get the 0 point for the control stick.
unsigned char command[] = {0x01};
N64_send(command, 1);
// read in data and dump it to N64_raw_dump
N64_get();
interrupts();
translate_raw_data();
/*
*/
}
void translate_raw_data()
{
// The get_N64_status function sloppily dumps its data 1 bit per byte
// into the get_status_extended char array. It's our job to go through
// that and put each piece neatly into the struct N64_status
int i;
memset(&N64_status, 0, sizeof(N64_status));
// line 1
// bits: A, B, Z, Start, Dup, Ddown, Dleft, Dright
for (i=0; i<8; i++) {
N64_status.data1 |= N64_raw_dump[i] ? (0x80 >> i) : 0;
}
// line 2
// bits: 0, 0, L, R, Cup, Cdown, Cleft, Cright
for (i=0; i<8; i++) {
N64_status.data2 |= N64_raw_dump[8+i] ? (0x80 >> i) : 0;
}
// line 3
// bits: joystick x value
// These are 8 bit values centered at 0x80 (128)
for (i=0; i<8; i++) {
N64_status.stick_x |= N64_raw_dump[16+i] ? (0x80 >> i) : 0;
}
for (i=0; i<8; i++) {
N64_status.stick_y |= N64_raw_dump[24+i] ? (0x80 >> i) : 0;
}
}
/**
* This sends the given byte sequence to the controller
* length must be at least 1
* Oh, it destroys the buffer passed in as it writes it
*/
void N64_send(unsigned char *buffer, char length)
{
// Send these bytes
char bits;
//bool bit;
// This routine is very carefully timed by examining the assembly output.
// Do not change any statements, it could throw the timings off
//
// We get 16 cycles per microsecond, which should be plenty, but we need to
// be conservative. Most assembly ops take 1 cycle, but a few take 2
//
// I use manually constructed for-loops out of gotos so I have more control
// over the outputted assembly. I can insert nops where it was impossible
// with a for loop
asm volatile ("#Starting outer for loop");
outer_loop:
{
asm volatile ("#Starting inner for loop");
bits=8;
inner_loop:
{
// Starting a bit, set the line low
asm volatile ("#Setting line to low");
N64_LOW; // 1 op, 2 cycles
asm volatile ("#branching");
if (*buffer >> 7) {
asm volatile ("#Bit is a 1");
// 1 bit
// remain low for 1us, then go high for 3us
// nop block 1
asm volatile ("nop\nnop\nnop\nnop\nnop\n");
asm volatile ("#Setting line to high");
N64_HIGH;
// nop block 2
// we'll wait only 2us to sync up with both conditions
// at the bottom of the if statement
asm volatile ("nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
);
} else {
asm volatile ("#Bit is a 0");
// 0 bit
// remain low for 3us, then go high for 1us
// nop block 3
asm volatile ("nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
"nop\n");
asm volatile ("#Setting line to high");
N64_HIGH;
// wait for 1us
asm volatile ("#end of conditional branch, need to wait 1us more before next bit");
}
// end of the if, the line is high and needs to remain
// high for exactly 16 more cycles, regardless of the previous
// branch path
asm volatile ("#finishing inner loop body");
--bits;
if (bits != 0) {
// nop block 4
// this block is why a for loop was impossible
asm volatile ("nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\n");
// rotate bits
asm volatile ("#rotating out bits");
*buffer <<= 1;
goto inner_loop;
} // fall out of inner loop
}
asm volatile ("#continuing outer loop");
// In this case: the inner loop exits and the outer loop iterates,
// there are /exactly/ 16 cycles taken up by the necessary operations.
// So no nops are needed here (that was lucky!)
--length;
if (length != 0) {
++buffer;
goto outer_loop;
} // fall out of outer loop
}
// send a single stop (1) bit
// nop block 5
asm volatile ("nop\nnop\nnop\nnop\n");
N64_LOW;
// wait 1 us, 16 cycles, then raise the line
// 16-2=14
// nop block 6
asm volatile ("nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\n");
N64_HIGH;
}
void N64_get()
{
// listen for the expected 8 bytes of data back from the controller and
// blast it out to the N64_raw_dump array, one bit per byte for extra speed.
// Afterwards, call translate_raw_data() to interpret the raw data and pack
// it into the N64_status struct.
asm volatile ("#Starting to listen");
unsigned char timeout;
char bitcount = 32;
char *bitbin = N64_raw_dump;
// Again, using gotos here to make the assembly more predictable and
// optimization easier (please don't kill me)
read_loop:
timeout = 0x3f;
// wait for line to go low
while (N64_QUERY) {
if (!--timeout)
return;
}
// wait approx 2us and poll the line
asm volatile (
"nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
"nop\nnop\nnop\nnop\nnop\n"
);
*bitbin = N64_QUERY;
++bitbin;
--bitcount;
if (bitcount == 0)
return;
// wait for line to go high again
// it may already be high, so this should just drop through
timeout = 0x3f;
while (!N64_QUERY) {
if (!--timeout)
return;
}
goto read_loop;
}
void print_N64_status()
{
//int i;
// bits: A, B, Z, Start, Dup, Ddown, Dleft, Dright
// bits: 0, 0, L, R, Cup, Cdown, Cleft, Cright
Serial.println();
Serial.print("Start: ");
Serial.println(N64_status.data1 & 16 ? 1:0);
Serial.print("Z: ");
Serial.println(N64_status.data1 & 32 ? 1:0);
Serial.print("B: ");
Serial.println(N64_status.data1 & 64 ? 1:0);
Serial.print("A: ");
Serial.println(N64_status.data1 & 128 ? 1:0);
Serial.print("L: ");
Serial.println(N64_status.data2 & 32 ? 1:0);
Serial.print("R: ");
Serial.println(N64_status.data2 & 16 ? 1:0);
Serial.print("Cup: ");
Serial.println(N64_status.data2 & 0x08 ? 1:0);
Serial.print("Cdown: ");
Serial.println(N64_status.data2 & 0x04 ? 1:0);
Serial.print("Cright:");
Serial.println(N64_status.data2 & 0x01 ? 1:0);
Serial.print("Cleft: ");
Serial.println(N64_status.data2 & 0x02 ? 1:0);
Serial.print("Dup: ");
Serial.println(N64_status.data1 & 0x08 ? 1:0);
Serial.print("Ddown: ");
Serial.println(N64_status.data1 & 0x04 ? 1:0);
Serial.print("Dright:");
Serial.println(N64_status.data1 & 0x01 ? 1:0);
Serial.print("Dleft: ");
Serial.println(N64_status.data1 & 0x02 ? 1:0);
Serial.print("Stick X:");
Serial.println(N64_status.stick_x, DEC);
Serial.print("Stick Y:");
Serial.println(N64_status.stick_y, DEC);
Serial.print("Stick Reset:");
Serial.println(N64_status.data2 & 128 ? 1:0);
}
void loop()
{
//int i;
//unsigned char data;
//unsigned char addr;
// Command to send to the gamecube
// The last bit is rumble, flip it to rumble
// yes this does need to be inside the loop, the
// array gets mutilated when it goes through N64_send
unsigned char command[] = {0x01};
// don't want interrupts getting in the way
noInterrupts();
// send those 3 bytes
N64_send(command, 1);
// read in data and dump it to N64_raw_dump
N64_get();
// end of time sensitive code
interrupts();
// translate the data in N64_raw_dump to something useful
translate_raw_data();
//Start:
Joystick.button(1, N64_status.data1 & 16 ? 1 : 0);
Joystick.X(N64_status.stick_x);
//Data for the Y axis seems to come out inverted
Joystick.Y(N64_status.stick_y * -1);
Joystick.send_now();
// DEBUG: print it
print_N64_status();
delay(10);
/*
*/
}
*Slight modifications by me; namely the TeensyLC Joystick partial implementation
Reply With Quote
Originally Posted by whiterabbit
