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/* SPDX-License-Identifier: MIT
*
* Copyright (C) 2020 jet tsang zeon-git. All Rights Reserved.
*/
package servo
import (
"fmt"
"git.jettsang.com/drivers/lobot/iface"
"git.jettsang.com/drivers/lobot/utils"
)
const (
// Unit conversions
maxPos uint16 = 1000
maxAngle float64 = 240
positionToAngle float64 = maxAngle / float64(maxPos) // 0.24
angleToPosition float64 = 1 / positionToAngle // 4.16
)
type Servo struct {
Protocol iface.Protocol
ID int
instructions InstructionMap
}
// New returns a new Servo.
func New(proto iface.Protocol, instructions InstructionMap, ID int) *Servo {
return &Servo{
Protocol: proto,
ID: ID,
instructions: instructions,
}
}
func (s *Servo) sendInstruction(i InstName, values []uint16) error {
r, ok := s.instructions[i]
if !ok {
return fmt.Errorf("can't send a unsupported instruction: %v", i)
}
if r.Access == RO {
return fmt.Errorf("can't sned a read-only instruction.")
}
var params []byte
switch r.Length {
case 1:
if len(values) != 1 {
return fmt.Errorf("invalid values length inputs.")
}
params = []byte{utils.Low(values[0])}
case 4:
if len(values) != 2 {
return fmt.Errorf("invalid values length inputs.")
}
params = []byte{
utils.Low(values[0]),
utils.High(values[0]),
utils.Low(values[1]),
utils.High(values[1]),
}
default:
return fmt.Errorf("invalid instruction length: %d", r.Length)
}
return s.Protocol.WriteData(s.ID, r.InstByte, params)
}
func (s *Servo) SendInstruction(i InstName, values []uint16) error {
return s.sendInstruction(i, values)
}
func (s *Servo) getData(i InstName) ([]byte, error) {
r, ok := s.instructions[i]
if !ok {
return nil, fmt.Errorf("can't send a unsupported instruction: %v", i)
}
if r.Access != RO {
return nil, fmt.Errorf("can't sned a read-only instruction.")
}
return s.Protocol.ReadData(s.ID, r.InstByte)
}
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