I can do the soldering if I have to. I also agree that the TFT should be mounted on the Mega. I can hardwire this shield and mount it remotely if I need to.
From my read of the following:
Understanding the Adafruit Motor Shield Library
most of the pins on the Uno part of the Mega are used for the motor shield.
the following is from AFMotor.h which I have included below these snipits and is the library that is called.
// Bit positions in the 74HCT595 shift register output
#define MOTOR1_A 2
#define MOTOR1_B 3
#define MOTOR2_A 1
#define MOTOR2_B 4
#define MOTOR4_A 0
#define MOTOR4_B 6
#define MOTOR3_A 5
#define MOTOR3_B 7
// Arduino pin names for interface to 74HCT595 latch
#define MOTORLATCH 12
#define MOTORCLK 4
#define MOTORENABLE 7
#define MOTORDATA 8
Maybe there are more that I don't recognise??
// Adafruit Motor shield library
// copyright Adafruit Industries LLC, 2009
// this code is public domain, enjoy!
/*
* Usage Notes:
* For PIC32, all features work properly with the following two exceptions:
*
* 1) Because the PIC32 only has 5 PWM outputs, and the AFMotor shield needs 6
* to completely operate (four for motor outputs and two for RC servos), the
* M1 motor output will not have PWM ability when used with a PIC32 board.
* However, there is a very simple workaround. If you need to drive a stepper
* or DC motor with PWM on motor output M1, you can use the PWM output on pin
* 9 or pin 10 (normally use for RC servo outputs on Arduino, not needed for
* RC servo outputs on PIC32) to drive the PWM input for M1 by simply putting
* a jumber from pin 9 to pin 11 or pin 10 to pin 11. Then uncomment one of the
* two #defines below to activate the PWM on either pin 9 or pin 10. You will
* then have a fully functional microstepping for 2 stepper motors, or four
* DC motor outputs with PWM.
*
* 2) There is a conflict between RC Servo outputs on pins 9 and pins 10 and
* the operation of DC motors and stepper motors as of 9/2012. This issue
* will get fixed in future MPIDE releases, but at the present time it means
* that the Motor Party example will NOT work properly. Any time you attach
* an RC servo to pins 9 or pins 10, ALL PWM outputs on the whole board will
* stop working. Thus no steppers or DC motors.
*
*/
// <BPS> 09/15/2012 Modified for use with chipKIT boards
#ifndef _AFMotor_h_
#define _AFMotor_h_
#include <inttypes.h>
#if defined(__AVR__)
#include <avr/io.h>
//#define MOTORDEBUG 1
#define MICROSTEPS 16 // 8 or 16
#define MOTOR12_64KHZ _BV(CS20) // no prescale
#define MOTOR12_8KHZ _BV(CS21) // divide by 8
#define MOTOR12_2KHZ _BV(CS21) | _BV(CS20) // divide by 32
#define MOTOR12_1KHZ _BV(CS22) // divide by 64
#define MOTOR34_64KHZ _BV(CS00) // no prescale
#define MOTOR34_8KHZ _BV(CS01) // divide by 8
#define MOTOR34_1KHZ _BV(CS01) | _BV(CS00) // divide by 64
#define DC_MOTOR_PWM_RATE MOTOR34_8KHZ // PWM rate for DC motors
#define STEPPER1_PWM_RATE MOTOR12_64KHZ // PWM rate for stepper 1
#define STEPPER2_PWM_RATE MOTOR34_64KHZ // PWM rate for stepper 2
#elif defined(__PIC32MX__)
//#define MOTORDEBUG 1
// Uncomment the one of following lines if you have put a jumper from
// either pin 9 to pin 11 or pin 10 to pin 11 on your Motor Shield.
// Either will enable PWM for M1
//#define PIC32_USE_PIN9_FOR_M1_PWM
//#define PIC32_USE_PIN10_FOR_M1_PWM
#define MICROSTEPS 16 // 8 or 16
// For PIC32 Timers, define prescale settings by PWM frequency
#define MOTOR12_312KHZ 0 // 1:1, actual frequency 312KHz
#define MOTOR12_156KHZ 1 // 1:2, actual frequency 156KHz
#define MOTOR12_64KHZ 2 // 1:4, actual frequency 78KHz
#define MOTOR12_39KHZ 3 // 1:8, acutal frequency 39KHz
#define MOTOR12_19KHZ 4 // 1:16, actual frequency 19KHz
#define MOTOR12_8KHZ 5 // 1:32, actual frequency 9.7KHz
#define MOTOR12_4_8KHZ 6 // 1:64, actual frequency 4.8KHz
#define MOTOR12_2KHZ 7 // 1:256, actual frequency 1.2KHz
#define MOTOR12_1KHZ 7 // 1:256, actual frequency 1.2KHz
#define MOTOR34_312KHZ 0 // 1:1, actual frequency 312KHz
#define MOTOR34_156KHZ 1 // 1:2, actual frequency 156KHz
#define MOTOR34_64KHZ 2 // 1:4, actual frequency 78KHz
#define MOTOR34_39KHZ 3 // 1:8, acutal frequency 39KHz
#define MOTOR34_19KHZ 4 // 1:16, actual frequency 19KHz
#define MOTOR34_8KHZ 5 // 1:32, actual frequency 9.7KHz
#define MOTOR34_4_8KHZ 6 // 1:64, actual frequency 4.8KHz
#define MOTOR34_2KHZ 7 // 1:256, actual frequency 1.2KHz
#define MOTOR34_1KHZ 7 // 1:256, actual frequency 1.2KHz
// PWM rate for DC motors.
#define DC_MOTOR_PWM_RATE MOTOR34_39KHZ
// Note: for PIC32, both of these must be set to the same value
// since there's only one timebase for all 4 PWM outputs
#define STEPPER1_PWM_RATE MOTOR12_39KHZ
#define STEPPER2_PWM_RATE MOTOR34_39KHZ
#endif
// Bit positions in the 74HCT595 shift register output
#define MOTOR1_A 2
#define MOTOR1_B 3
#define MOTOR2_A 1
#define MOTOR2_B 4
#define MOTOR4_A 0
#define MOTOR4_B 6
#define MOTOR3_A 5
#define MOTOR3_B 7
// Constants that the user passes in to the motor calls
#define FORWARD 1
#define BACKWARD 2
#define BRAKE 3
#define RELEASE 4
// Constants that the user passes in to the stepper calls
#define SINGLE 1
#define DOUBLE 2
#define INTERLEAVE 3
#define MICROSTEP 4
/*
#define LATCH 4
#define LATCH_DDR DDRB
#define LATCH_PORT PORTB
#define CLK_PORT PORTD
#define CLK_DDR DDRD
#define CLK 4
#define ENABLE_PORT PORTD
#define ENABLE_DDR DDRD
#define ENABLE 7
#define SER 0
#define SER_DDR DDRB
#define SER_PORT PORTB
*/
// Arduino pin names for interface to 74HCT595 latch
#define MOTORLATCH 12
#define MOTORCLK 4
#define MOTORENABLE 7
#define MOTORDATA 8
class AFMotorController
{
public:
AFMotorController(void);
void enable(void);
friend class AF_DCMotor;
void latch_tx(void);
uint8_t TimerInitalized;
};
class AF_DCMotor
{
public:
AF_DCMotor(uint8_t motornum, uint8_t freq = DC_MOTOR_PWM_RATE);
void run(uint8_t);
void setSpeed(uint8_t);
private:
uint8_t motornum, pwmfreq;
};
class AF_Stepper {
public:
AF_Stepper(uint16_t, uint8_t);
void step(uint16_t steps, uint8_t dir, uint8_t style = SINGLE);
void setSpeed(uint16_t);
uint8_t onestep(uint8_t dir, uint8_t style);
void release(void);
uint16_t revsteps; // # steps per revolution
uint8_t steppernum;
uint32_t usperstep, steppingcounter;
private:
uint8_t currentstep;
};
uint8_t getlatchstate(void);
#endif
I have connected the motor shield to the Mega and confirmed correct operation of a piece of example code and then manually connected all the digital pins except 13. I also connected +5V and 0V for power and it sort of works but not correctly. just vibrates the stepper motor and moves a little bit where it should do a full revolution as part of the test code.
This implies to me that there is another pin that needs connecting.
Time to pack it in tonight.
I will try a few more pin connections tomorrow
Thanks again for your help.