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Topic: Leonardo with the TLC5940 (Read 6 times) previous topic - next topic


Okay so I noticed last night while building a circuitboard that the TLC5940 Grayscale clock (for the PWM function) is connected to the INT1 pin when set-up with an ATmega328p.  When connecting it up like that on the 32U4, I noticeced the INT1 pin is also the SDA pin (for I2C/TWI).  Unfortunatly my project requires the I2C bus for a different IC.  

Can I change the grayscale pin for this to another pin and will still work?

Hi funkyguy4000

This fix works succesfully with my Leonardo. In my project, this library controls the TLCs using ICSP (center wires) and the 5, 9, 10 pins on Leonardo board. Moreover, i'm sending data to an Colorduino through I2C using SDA and SCL pins.

They works perfectly without change any pin map on this fix!


No changes at all? Its just if you put them on the right pins, it works?

Wow.  I haven't gotten a chance to try this, I've been too busy with my studies.
Accelerate to 88 miles per hour.


Apr 04, 2013, 05:05 pm Last Edit: Apr 04, 2013, 08:08 pm by Coding Badly Reason: 1
Hi -

This code was really helpful to me, but in fact it isn't the only fix you need for the Leonardo to work with the TLC 5940.  I tried running a servo motor off of it, but the pulse width was wrong.  As it turns out there are some issues with the Timers used in Leonardo that are only half-addressed in the servo header file (as the GSCLK is running about 16 times too fast), but if you look at the Tlc5940.cpp file than you can figure it out.

This is the code that your tlc_servos.h file should look like if you want to run servos off of the TLC5940 with your Leonardo.



Code: [Select]
/*  Copyright (c) 2009 by Alex Leone <acleone ~AT~ gmail.com>

   This file is part of the Arduino TLC5940 Library.

   The Arduino TLC5940 Library is free software: you can redistribute it
   and/or modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation, either version 3 of the
   License, or (at your option) any later version.

   The Arduino TLC5940 Library is distributed in the hope that it will be
   useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with The Arduino TLC5940 Library.  If not, see
   <http://www.gnu.org/licenses/>. */

#ifndef TLC_SERVOS_H
#define TLC_SERVOS_H

/** \file
   TLC servo functions. */

#include <avr/io.h>
#include "Tlc5940.h"

/** The maximum angle of the servo. */
#define SERVO_MAX_ANGLE     180
/** The 1ms pulse width for zero degrees (0 - 4095). Default 204 */
#define SERVO_MIN_WIDTH     204
/** The 2ms pulse width for 180 degrees (0 - 4095). Default 410*/
#define SERVO_MAX_WIDTH     410
/** The top value for XLAT and BLANK pulses.  This is with the div8 prescale,
   \f$\displaystyle f_{PWM} = \frac{f_{osc}}{2 * 8 * SERVO\_TIMER1\_TOP} \f$
   The default is 20000, which corresponds to 50Hz. */
#define SERVO_TIMER1_TOP    20000
/** The top value for GSCLK pulses.  Related to SERVO_TIMER1_TOP by
   \f$\displaystyle SERVO\_TIMER2\_TOP =
       \frac{2 * 8 * SERVO\_TIMER1\_TOP}{4096} - 1 \f$
   The default is 77. */
#define SERVO_TIMER2_TOP    77

void tlc_initServos(uint8_t initAngle = 0);
void tlc_setServo(TLC_CHANNEL_TYPE channel, uint8_t angle);
uint8_t tlc_getServo(TLC_CHANNEL_TYPE channel);
uint16_t tlc_angleToVal(uint8_t angle);
uint8_t tlc_valToAngle(uint16_t value);

/** \addtogroup ExtendedFunctions
   \code #include "tlc_servos.h" \endcode
   - void tlc_initServos(uint8_t initAngle = 0) - initializes the tlc for
   - void tlc_setServo(TLC_CHANNEL_TYPE channel, uint8_t angle) - sets a
           servo to an angle
   - uint8_t tlc_getServo(TLC_CHANNEL_TYPE channel) - gets the currently set
           servo angle */
/* @{ */

/** Initializes the tlc.
   \param initAngle the initial angle to set all servos to
           (0 - SERVO_MAX_ANGLE). */
void tlc_initServos(uint8_t initAngle)
   TCCR1B &= ~(_BV(CS12) | _BV(CS11) | _BV(CS10)); // stop timer1
   TCNT1 = 0;
#ifdef TLC_ATMEGA_8_H
   uint8_t oldTCCR2 = TCCR2;
   TCCR2 = 0;
   TCNT2 = 0;
   TCCR2 = oldTCCR2;
#elif defined(TLC_TIMER3_GSCLK)
uint8_t oldTCCR3B = TCCR3B;
TCCR3B = 0;
   TCNT3 = 0;
   TCCR3B = oldTCCR3B;
   uint8_t oldTCCR2B = TCCR2B;
   TCCR2B = 0;
   TCNT2 = 0;
   TCCR2B = oldTCCR2B;
   TCCR1B |= _BV(CS11); // start timer1 with div 8 prescale

/** Sets a servo on channel to angle.
   \param channel which channel to set
   \param angle (0 - SERVO_MAX_ANGLE) */
void tlc_setServo(TLC_CHANNEL_TYPE channel, uint8_t angle)
   Tlc.set(channel, tlc_angleToVal(angle));

/** Gets the current angle that channel is set to.
   \param channel which channel to get */
uint8_t tlc_getServo(TLC_CHANNEL_TYPE channel)
   return tlc_valToAngle(Tlc.get(channel));

/** Converts and angle (0 - SERVO_MAX_ANGLE) to the inverted tlc channel value
   (4095 - 0). */
uint16_t tlc_angleToVal(uint8_t angle)
   return 4095 - SERVO_MIN_WIDTH - (
           ((uint16_t)(angle) * (uint16_t)(SERVO_MAX_WIDTH - SERVO_MIN_WIDTH))
           / SERVO_MAX_ANGLE);

/** Converts an inverted tlc channel value (4095 - 0) into an angle (0 -
uint8_t tlc_valToAngle(uint16_t value)
   return SERVO_MAX_ANGLE * (4095 - SERVO_MIN_WIDTH - value)

/* @} */


Moderator edit: [code] [/code] tags added.


Nvermind. I have figured it out myself.
The only thing I do not understand so far is what you do with the Rx Led pin...


I know this post is already dated. However, since you asked for the pin mapping and figured it out yourself it would have been cool if you would have provided that mapping. Maybe you still have it somewhere and could post it here for reasons of documentation and helping out a n00b.

Thank you.


I echo minuteman's sentiments -- I would love to see the resolution to this.

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