and... how about to feed the arduino mega with a car battery?

Should be no problem. Take care if it's not the car battery but the car electrical system because there you might get voltage spikes that may hurt the Arduino.

Put your code with the #if stuff into another file (any .cpp in the same directory). The main sketch is transformed into a .cpp file by the IDE which then looks about this:

Code:

#line 1 "sketch_may08a.ino"

#include "Arduino.h"
void setup();
void loop();
long mytest();
float mytest();
#line 2
void setup() {
  // put your setup code here, to run once:
}

void loop() {
  // put your main code here, to run repeatedly:
}

#ifdef TESTING
long mytest()
{
}
#else
float mytest()
{
}
#endif

As you can see the IDE is providing the prototypes and don't care for the precompiler directives. It doesn't do that for the other files, just for the main sketch (*.ino).

same results. one thing, the chip speed is 3.3mhz, do i have that set correctly?

Where is this comment coming from then?

Code:

max clock is 20MHz, so can set high speed

You have to slow down the communication in this case then:

Code:

SPI.setClockDivider(SPI_CLOCK_DIV8); // max speed is 3MHz, we choose 2MHz

Does that change anything?

Just to be sure we don't get problems from operator priority, please try this version too:

Code:

//4k e2prom and cpu supervisor

#include <SPI.h>
#define WRITE 2
#define READ  3
#define WREN  6
#define RDSR  5
#define WRSR  1

unsigned int address = 0x01;
byte outval = 250;
byte invalue;

void setup(){
  Serial.begin(9600);
  Serial.println("RESET");

  // set up to match device datasheet
  SPI.begin(); // sets up pin modes etc.
  SPI.setBitOrder(MSBFIRST);
  SPI.setDataMode(SPI_MODE0);
  SPI.setClockDivider(SPI_CLOCK_DIV2); // max clock is 20MHz, so can set high speed

  // Enable writing
  digitalWrite(SS, LOW);
  SPI.transfer(WREN);
  digitalWrite(SS, HIGH);

  // Initialize status register
  digitalWrite(SS, LOW);
  SPI.transfer(WRSR);
  SPI.transfer(0x00);
  digitalWrite(SS, HIGH);

  // Latch enable write again (don't know why this is necessary)
  digitalWrite(SS, LOW);
  SPI.transfer(WREN);
  digitalWrite(SS, HIGH);

  // write a value to address 0x01
  digitalWrite(SS,LOW);
  SPI.transfer(WRITE | ((address & 0x0100) ? 8 : 0));
  SPI.transfer(address & 0xFF);
  SPI.transfer(outval);
  digitalWrite(SS, HIGH);

  // read a value from address 0x01
  digitalWrite(SS,LOW);
  SPI.transfer(READ | ((address & 0x0100) ? 8 : 0));
  SPI.transfer(address & 0xFF);
  invalue = SPI.transfer(0x00);
  digitalWrite(SS,HIGH);
  Serial.print("Read Data = ");
  Serial.println(invalue,DEC);
}

void loop() {
}

To avoid bigger troubles plan for a Mega2560 from the beginning. Although you might get it done with UNO (or compatible) with some hassles and software emulations your live will be much easier if you have 4 hardware serial interfaces to use.

There is absolutely no need to hard-code your Wifi settings into the sketch. You can store the credentials into the EEPROM for example to ensure you have them after a reset again.

Do you have a Mega2560? In this case: yes because this Arduino has 4 serial interfaces. Otherwise: No.

If you provide a bit more information we might give you hints how you can circumvent your problems.

Did you activate software SPI in Sd2Card.h? If you did, that would explain your misses because interrupts are disabled during SPI transfers. Otherwise I currently cannot explain it. I probably would try to increase the serial buffer to a value greater than 79 bytes to be sure the buffer can hold a complete record.

I'm using an Arduino Pro Mini 328 from SparkFun.  Any guidance on determining which pins and which timer  I can use for AltSoftSerial?

The Pro Mini should behave like a standard UNO in this context. That means the pins are D8 and D9 and you loose PWM on pin D10.

das breakout Board dass du mir empfohlen hast ist ja leider ausverkauft.

Nicht an Lager heisst doch nicht ausverkauft. Bei SparkFun gibt es das Board noch (https://www.sparkfun.com/products/11125), also kannst Du es bei Boxtec (oder einem anderen Anbieter, der SparkFun-Produkte führt) bestellen.

Code:

while (Serial.available()) Serial.read();

... does empty your incoming buffer.

But your description sounds like you're having another problem. Is it possible that you have a loopback at the serial interface? Does it work if you don't print out the same character as you're receiving?

this is what interil told me to look at, i cannot however translate this to arduino

Looks like the chip has to be initialized a bit further before being ready:

Code:

//4k e2prom and cpu supervisor

#include <SPI.h>
#define WRITE 2
#define READ  3
#define WREN  6
#define RDSR  5
#define WRSR  1

unsigned int address = 0x01;
byte outval = 250;
byte invalue;

void setup(){
  Serial.begin(9600);
  Serial.println("RESET");

  // set up to match device datasheet
  SPI.begin(); // sets up pin modes etc.
  SPI.setBitOrder(MSBFIRST);
  SPI.setDataMode(SPI_MODE0);
  SPI.setClockDivider(SPI_CLOCK_DIV2); // max clock is 20MHz, so can set high speed

  // Enable writing
  digitalWrite(SS, LOW);
  SPI.transfer(WREN);
  digitalWrite(SS, HIGH);

  // Initialize status register
  digitalWrite(SS, LOW);
  SPI.transfer(WRSR);
  SPI.transfer(0x00);
  digitalWrite(SS, HIGH);

  // Latch enable write again (don't know why this is necessary)
  digitalWrite(SS, LOW);
  SPI.transfer(WREN);
  digitalWrite(SS, HIGH);

  // write a value to address 0x01
  digitalWrite(SS,LOW);
  SPI.transfer(WRITE | (address & 0x0100) ? 8 : 0);
  SPI.transfer(address & 0xFF);
  SPI.transfer(outval);
  digitalWrite(SS, HIGH);

  // read a value from address 0x01
  digitalWrite(SS,LOW);
  SPI.transfer(READ | (address & 0x0100) ? 8 : 0);
  SPI.transfer(address & 0xFF);
  invalue = SPI.transfer(0x00);
  digitalWrite(SS,HIGH);
  Serial.print("Read Data = ");
  Serial.println(invalue,DEC);
}

void loop() {
}

What's the output of this sketch?

How did you connect the sine wave to the Arduino? Is the sine wave going from 0V to 5V or from -5V to 5V?

delayMicroseconds() can be called with values up to 13107, if you call it with higher value you'll have a bit overrun. So calling it with 14108 is about the same as calling it with 1000.

Great, thanks for the info.  I'll use softserial for the RS485 comms then.  My needs are very simple but I need to be able to program with the MAX485 connected.

SoftwareSerial is not a drop-in replacement for a hardware serial interface. Reliable communication is possible up to 9600 baud, in some cases up to 38400 baud. During the transfer of a byte over the SoftwareSerial interface (independent of the direction) the processor is completely absorbed and cannot be used for anything other. If you can live with this, use the SoftwareSerial. Otherwise you might take a look at the AltSoftSerial library (http://www.pjrc.com/teensy/td_libs_AltSoftSerial.html) or use another Arduino model (Leonardo or Mega) which has more hardware serial interfaces.

Post the code your using for this.