component carousel """Orient a toolchanger carousel using various encoding schemes

.B loadrt carousel pockets=\\fIN\\fR[,\\fIN\\fR]
.B encoding=\\fIssss\\fR[,\\fIsss\\fR]\\fB
.B num_sense=\\fIN\\fR[,\\fIN\\fR]
.B dir=\\fIN\\fR[,\\fIN]

.RS 4
.TP
\\fBpockets\\fR The number of pockets in each toolchanger.
Use up to 8 numbers separated by commas to create multiple carousel components.
.TP
\\fBencoding\\fR The position encoding.
gray, binary, bcd, index, edge or single. Default = 'gray'
.TP
\\fBnum_sense\\fR The number of position sense pins.
Default = 4.
.TP
\\fBdir\\fR Set to 1 for unidirectional or  2 for bidirectional operation.
Default = bidirectional
.TP
\\fBparity\\fR Set to 1 for odd parity, 0 for even parity checking.
Default = 0 (even)
.RE""";

description """This component is intended to help operate various types of
carousel-type toolchangers. 
The component can be configured to operate with binary, binary-coded decimal (BCD)
or gray-coded position feedback, with an individual sensor for each tool position
or with a sensor at each tool position and a separate index.

Both unidirectional and bidirectional systems are supported and those that reverse
against a stop when in position. 

The number of carousel component instances created depends on the number of
entries in the 'pockets' modparam. For example

.B loadrt carousel pockets=10,10,8

Would create 3 carousel instances with 10, 10 and 8 pockets. The other 
parameters are optional. If absent then defaults will be used. Any missing
entry will assume the previous value.

When the enable pin is set to true the component will immediately set the 
"active" pin to true and then (for a bidirectional instance) calculate the
shortest path to the requested pocket number. The appropriate motor direction
output pins will then be set. Bit outputs for forward and reverse are provided
as well as a three-state velocity output for driving a DC motor PWM or a 
velocity-mode stepgen. 

The component will monitor the carousel position and, when the correct position
is reached, set the motor-control pins to 0, set "active" to 0 and set "ready"
to 1.

In index mode the behaviour is slightly different. The first time that the "enable"
pin is set; the carousel will rotate forwards until
both the index and pulse inputs are true. If there is no pulse line at the
index position then a HAL "or2" function can be used to allow the index sensor
to toggle both inputs. Setting "enable" low does not halt the homing move, so if
homing on first tool change is not needed then the enable pin can be toggled by
an axis homing pin or a script. \\fBedge\\fR is a special case of index mode for tool
changers with pockets on both the rising and falling edges of the position sensor.
(Seen on at least one Denford Orac.)

For tool changers which lock the carousel against a stop the \\fBrev-pulse\\fR pin can
be set to a non-zero value. The motor-rev pin will then be set for this many seconds
at the completion of the tool search and at the same time the reverse duty/cycle
velocity value will be sent to the motor-vel pin. 
""";

pin in  signed pocket-number """The pocket to move to when the .enable pin goes high. If the value
passed is higher than the number of pockets specified in the "pockets" modparam then modulo arithmetic
is used. This is intended to allow the use of multiple tools in the same holder, as is sometimes
useful with lathes.""";
pin in  bit    enable "Set this pin high to start movement. Setting it low will stop movement";
pin out bit    active "indicates that the component is active";
pin out bit    ready "This pin goes high when the carousel is in-position";
pin in  bit    strobe = 1 """Use this pin to indicate that the position feedback is valid. Often
provided by binary encoders""";
pin  in bit    parity_ """Some encoders supply a parity bit, if this is connected then the
parity-error output bit will indicate parity errors""";
pin in  bit    sense-# [32:personality] """Carousel position feedback pins. In 'index' mode there 
will be only 2 pins. sense-0 is the index and sense-1 is the pocket sensor.""";
pin in float rev-pulse """The duration in seconds for which a ratchet changer (Boxford, Emco)
should pulse the reverse pin to lock the holder""";
pin in float fwd-dc "Velocity or duty cycle when forwards rotation is desired";
pin in float rev-dc " Velocity or duty cycle when reverse rotation is desired";
pin in float hold-dc "Duty cycle when carousel is in-position (to hold against stop)";
pin in  bit    jog-fwd "Jog the carousel forwards one tool position";
pin in  bit    jog-rev """Jog the carousel in reverse (only if dir = 2).
It is very important that these pins should be debounced and should probably
also be interlocked to only operate when the machine is idle.""";
pin out bit    motor-fwd "Indicates the motor should run forwards (bigger numbers)";
pin out bit    motor-rev "Indicates the motor should run reverse.";
pin out bit    parity-error "Indicates a parity error";
pin out signed current-position "This pin indicates the current position feedback";
pin out float  motor_vel "The duty-cycle or velocity to drive a DC motor or stepgen";

param r  signed state = 0 "Current component state";
param r  bit    homing  = 0 "Shows that homing is in progress. Only used for index mode";
param r  bit    homed = 0 "Shows that homing is complete. Only used in index and edge modes";
param r  float  timer "Shows the value of the internal timer";

option count_function;
option extra_setup;

license "GPL";
author "andy pugh";

variable int inst_sense;
variable int inst_dir;
variable int inst_pockets;
variable int inst_code;
variable int inst_parity;
variable int old_index = 0;
variable int target;
function _ ;

;;

int default_pockets = 8;
int default_code = 'G';
int default_dir = 2;
int default_sense = 4;
int default_parity = 0;

#define MAX_CHAN 8
static int pockets[MAX_CHAN] = {-1};
RTAPI_MP_ARRAY_INT(pockets, MAX_CHAN, "The number of pockets in each carousel")
static char *encoding[MAX_CHAN];
RTAPI_MP_ARRAY_STRING(encoding, MAX_CHAN, "Position feedback type")
static int dir[MAX_CHAN] = {-1};
RTAPI_MP_ARRAY_INT(dir, MAX_CHAN, 
                    "set to 2 if the carousel is bidirectional")
static int num_sense[MAX_CHAN] = {-1};
RTAPI_MP_ARRAY_INT(num_sense, MAX_CHAN, "The number of sense pins to create")
// We have a hal pin and a modparam with the same name. From the user
// point of view I think that makes sense. In the code parity[] is the modparam,
// parity_ is the hal pin.
static int parity[MAX_CHAN] = {-1};
RTAPI_MP_ARRAY_INT(parity, MAX_CHAN, "0 for even parity, 1 for odd")

FUNCTION(_){
    int i, d, pow;
    int pcalc = 0;
    int mod_pocket = 0;
    int p = 0;
    unsigned int mask;

    switch inst_code{
    case 'G': // Gray Code
        for (i = 0; i < inst_sense ; i++) {
            p += sense(i) << i;
        pcalc ^= sense(i);
        }
        for(mask = p >> 1 ; mask != 0 ; mask = mask >> 1){
            p ^= mask;
        }
        break;
    case 'B': // Straight Binary
        for (i = 0; i < inst_sense ; i++) {
            p += sense(i) << i;
        pcalc ^= sense(i);
        }
        break;
    case 'D': // BCD
        i = 0;
        pow = 1;
        while (i < inst_sense){
            int lim;
            d = 0;
            for (lim = i + 4; i < lim && i < inst_sense; i++) {
                d += sense(i) << (i % 4);
                pcalc ^= sense(i);
            }
            p += d * pow;
            pow *= 10;
        }
        break;
    case 'S': // individual sensors
        for (i = inst_sense - 1; sense(i) == 0 && i > 0 ; i--) {}
        if (sense(i)) 
            p = i + 1;
        break;
    case 'I': // index + position.
        p = current_position;
        if (homed){
            if ( !old_index && sense(1) ){
                if (motor_fwd){
                    p += 1;
                    if (p > inst_pockets) p -= inst_pockets;
                }
                if (motor_rev) {
                    p -= 1;
                    if (p < 1) p += inst_pockets;
                }
            }
            old_index = sense(1);
        }
        break;
    case 'E': // index + position, both edges.
        p = current_position;
        if (homed){
            if ( old_index != sense(1) ){
                if (motor_fwd){
                    p += 1;
                    if (p > inst_pockets) p -= inst_pockets;
                }
                if (motor_rev) {
                    p -= 1;
                    if (p < 1) p += inst_pockets;
                }
            }
            old_index = sense(1);
        }
        break;
    
    }

    if (strobe) {
        current_position = p;
        parity_error = (pcalc != (inst_parity ^ parity_));
    }
    mod_pocket = ((pocket_number - 1) % inst_pockets) + 1;
    // mod is odd with negatives, so just in case
    if (mod_pocket < 1) mod_pocket = 1;
    if (mod_pocket > inst_pockets) mod_pocket = inst_pockets;
    switch (state){
    case 0: // waiting at start
        if (jog_fwd || (jog_rev && inst_dir == 2))  {
            if ((inst_code == 'I' || inst_code == 'E') && ! homed){
                state = 10;
                break;
            }
            target = current_position + jog_fwd - jog_rev;
            if (target > inst_pockets ) target = 1;
            if (target < 1) target = inst_pockets;
            if (jog_fwd){
                motor_fwd = 1;
                motor_rev = 0;
                motor_vel = fwd_dc;
            }
            if (jog_rev){
                motor_fwd = 0;
                motor_rev = 1;
                motor_vel = rev_dc;
            }
            active = 1;
            state = 5;
            break;
        }
        motor_vel = hold_dc;
        if (! enable) return ;
        active = 1;
        if ((inst_code == 'I' || inst_code == 'E') && ! homed){
            state = 10;
            break;
        }
        state = 1;
        ready = 0;
    case 1: // choose direction
        if (mod_pocket < 1 || mod_pocket > inst_pockets) {
            state = 0;
            return;
        }
        if (inst_dir == 2){
            if (current_position < mod_pocket){
                if (mod_pocket - current_position > (inst_pockets / 2)) {
                    motor_fwd = 0;
                    motor_rev = 1;
                    motor_vel = rev_dc;
                } else {
                    motor_fwd = 1;
                    motor_rev = 0;
                    motor_vel = fwd_dc;
                }
            } else {
                if (current_position - mod_pocket > (inst_pockets / 2)) {
                    motor_fwd = 1;
                    motor_rev = 0;
                    motor_vel = fwd_dc;
                } else {
                    motor_fwd = 0;
                    motor_rev = 1;
                    motor_vel = rev_dc;
                }
            }
        } else {
            motor_fwd = 1;
            motor_rev = 0;
            motor_vel = fwd_dc;
        }
        state = 2;
    case 2: // moving
        if ((current_position != mod_pocket) && enable) return;
        if (rev_pulse > 0){
	    motor_fwd = 0;
            motor_rev = 1;
            motor_vel = rev_dc;
            timer = rev_pulse;        
	    state = 3;
        } else {
            motor_fwd = 0;
            motor_rev = 0;
            motor_vel = hold_dc;
            active = 0;
            if (enable) ready = 1;
            state = 4;
            break;
        }
    case 3:
	timer -= fperiod;
        if (timer > 0) break;
        state = 4;
        motor_fwd = 0;
        motor_rev = 0;
        motor_vel = hold_dc;
        active = 0;
        if (enable) ready = 1;
    case 4: //waiting for enable to go false
        if (enable) return;
        state = 0;
        break;
    case 5: //jogging fwd/rev
        if (current_position != target) return;
        motor_fwd = 0;
        motor_rev = 0;
        motor_vel = hold_dc;
        active = 0;
        if (jog_fwd || jog_rev) return; // require button release to jog again
        state = 0;
        break;
    case 10: // start of homing
        homed = 0;
        homing = 1;
        motor_fwd = 1;
        motor_rev = 0;
        motor_vel = fwd_dc;
        state = 11;
    case 11: // waiting for index & pulse
        if  ( (! old_index) && (sense(0) && sense(1)) ){ // index found
            current_position = 1;
            homed = 1;
            homing = 0;
            active = 0;
            motor_fwd = 0;
            motor_rev = 0;
            motor_vel = 0;
            state = 0;
        }
        old_index = (sense(0) && sense(1));
        break; // So that we don't see the tool1 pulse twice
    }
}

EXTRA_SETUP(){
    if (pockets[extra_arg] > 0) default_pockets = pockets[extra_arg];
    if (encoding[extra_arg] == NULL) {
        //it's already default_code
    } else if (strncmp(encoding[extra_arg], "binary", 6) == 0) {
        default_code = 'B';
    } else if (strncmp(encoding[extra_arg], "bcd", 3) == 0) {
        default_code = 'D';
    } else if (strncmp(encoding[extra_arg], "single", 6) == 0) {
        default_code = 'S';
    } else if (strncmp(encoding[extra_arg], "index", 5) == 0) {
        default_code = 'I';
    } else if (strncmp(encoding[extra_arg], "edge", 4) == 0) {
        default_code = 'E';
    }

    if (dir[extra_arg] > 0)  default_dir = (dir[extra_arg] > 1)? 2:1;

    if (parity[extra_arg] != -1) default_parity = parity[extra_arg];
    
    if (default_code == 'I') {
        default_sense = 2;
    } else if (num_sense[extra_arg] > 0 ) {
        default_sense = num_sense[extra_arg];
    }
    
    inst_pockets = default_pockets;
    inst_code = default_code;
    inst_dir = default_dir;
    inst_sense = default_sense;
    inst_parity = default_parity;

    if (inst_code == 'S' && inst_sense < inst_pockets) inst_sense = inst_pockets;
    personality = inst_sense;

    return 0;
}

int get_count(void){
    int i;
    for (i = 0; pockets[i] != 0 && i < MAX_CHAN; i++){}
    if (i == 0) return 1 ;
    return i;
}