Gracias por la respuesta.
El conversor es este: http://www.ledsandchips.com/232?filter_name=adc&filter_category_id=60
En esa misma página se ofrece un código para conectarlo a Arduino UNO. Yo creo que no usa exactamente la biblioteca SPI, sino unas rutinas subrutinas específicas.
El programa ejemplo que ofrece el vendedor del módulo es este: (he puesto en rojo lo que yo creo que constituye la rutina de comunicación entre Arduino y TM7709)
Mi problema es que uso Arduino MEGA y no sé como hacer la migración de pines.
//TM7709 24bit ADC module arduino sketch
//default connection arduino UNO
//DRDY = 11
//ADIO = 12
//SCLK = 13
#define TM7710_DRDY 3
#define TM7710_ADIO 4
#define TM7710_ADIO_OUT() DDRB|=1<<4
#define TM7710_ADIO_IN() DDRB&=~(1<<4)
#define Set_TM7710_SCLK() PORTB|=1<<5
#define Set_TM7710_ADIO() PORTB|=1<<4
#define Clr_TM7710_SCLK() PORTB&=~(1<<5)
#define Clr_TM7710_ADIO() PORTB&=~(1<<4)
unsigned char x[3];
long Result;
float vref=4.89;
void TM7710_start(void)
{
Clr_TM7710_ADIO();
delayMicroseconds(1);
Clr_TM7710_SCLK();
delayMicroseconds(1);
}
void TM7710_stop(void)
{
Clr_TM7710_ADIO();
delayMicroseconds(1);
Set_TM7710_SCLK();
delayMicroseconds(1);
Set_TM7710_ADIO();
delayMicroseconds(1);
}
void TM7710_write(unsigned char dd)
{
unsigned char i;
for(i=8;i>0;i--)
{
if(dd&0x80)
Set_TM7710_ADIO();
else
Clr_TM7710_ADIO();
delayMicroseconds(1);
Set_TM7710_SCLK();
delayMicroseconds(1);
Clr_TM7710_SCLK();
dd<<=1;
}
}
unsigned char TM7710_read(void)
{
unsigned char data=0,i;
for(i=0;i<8;i++)
{
Set_TM7710_SCLK();
data=data<<1;
if((PINB&(1<<TM7710_ADIO))==(1<<TM7710_ADIO))
{
data=data+1;
}
delayMicroseconds(1);
Clr_TM7710_SCLK();
delayMicroseconds(1);
}
return data;
}
void TM7710_Init()
{
TM7710_ADIO_OUT();
delay(100);
TM7710_stop();
TM7710_start();
TM7710_write(0xBF);
TM7710_write(0x20); //Gain=128
//TM7710_write(0x00); //Gain=16
TM7710_stop();
}
void setup()
{
DDRB|=1<<5 ;
delay(1000);
Serial.begin(57600);
Serial.println("TM7709 24bit ADC Module");
TM7710_Init();
}
void loop()
{
while((PINB&(1<<TM7710_DRDY))==(1<<TM7710_DRDY));
TM7710_start();
TM7710_write(0x7F);
TM7710_ADIO_IN();
for(unsigned char j=0;j<3;j++)
{
x[j]=TM7710_read();
}
TM7710_ADIO_OUT();
TM7710_stop();
Result=x[0];
Result = Result * 256;
Result = Result + x[1];
Result = Result * 256;
Result = Result + x[2];
Result = Result - 6912000;
double volt = Result * vref /16 / 6912000;
printFloat(volt,6);
Serial.println(" V ");
}
void printFloat(float value, int places) {
// this is used to cast digits
int digit;
float tens = 0.1;
int tenscount = 0;
int i;
float tempfloat = value;
// if value is negative, set tempfloat to the abs value
// make sure we round properly. this could use pow from
//<math.h>, but doesn't seem worth the import
// if this rounding step isn't here, the value 54.321 prints as
// calculate rounding term d: 0.5/pow(10,places)
float d = 0.5;
if (value < 0)
d *= -1.0;
// divide by ten for each decimal place
for (i = 0; i < places; i++)
d/= 10.0;
// this small addition, combined with truncation will round our
tempfloat += d;
if (value < 0)
tempfloat *= -1.0;
while ((tens * 10.0) <= tempfloat) {
tens *= 10.0;
tenscount += 1;
}
// write out the negative if needed
if (value < 0)
Serial.print('-');
if (tenscount == 0)
Serial.print(0, DEC);
for (i=0; i< tenscount; i++) {
digit = (int) (tempfloat/tens);
Serial.print(digit, DEC);
tempfloat = tempfloat - ((float)digit * tens);
tens /= 10.0;
}
// if no places after decimal, stop now and return
if (places <= 0)
return;
// otherwise, write the point and continue on
Serial.print('.');
for (i = 0; i < places; i++) {
tempfloat *= 10.0;
digit = (int) tempfloat;
Serial.print(digit,DEC);
// once written, subtract off that digit
tempfloat = tempfloat - (float) digit;
}
}
