© 1997-2013 Designer Systems
Page 3 of 8
INTERFACE 13.04.13 Revision 1.00
Servo 7 position
R13
P
P
P
P
P
P
P
P
P..P = Servo position 0 to 255 (0.5mS to 2.50mS)
Servo 7 control
R14
A
B
C
D
S
S
S
S
A = Operate (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start control (0 – Disabled 1 – Enabled)
D = Speed control (0 – Disabled 1 – Enabled)
S..S = Servo speed value 0 to 15 (0 = slowest)
Servo 8 position
R15
P
P
P
P
P
P
P
P
P..P = Servo position 0 to 255 (0.5mS to 2.50mS)
Servo 8 control
R16
A
B
C
D
S
S
S
S
A = Operate (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start control (0 – Disabled 1 – Enabled)
D = Speed control (0 – Disabled 1 – Enabled)
S..S = Servo speed value 0 to 15 (0 = slowest)
Servo 9 position
R17
P
P
P
P
P
P
P
P
P..P = Servo position 0 to 255 (0.5mS to 2.50mS)
Servo 9 control
R18
A
B
C
D
S
S
S
S
A = Operate (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start control (0 – Disabled 1 – Enabled)
D = Speed control (0 – Disabled 1 – Enabled)
S..S = Servo speed value 0 to 15 (0 = slowest)
Servo 10 position
R19
P
P
P
P
P
P
P
P
P..P = Servo position 0 to 255 (0.5mS to 2.50mS)
Servo 10 control
R20
A
B
C
D
S
S
S
S
A = Operate (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start control (0 – Disabled 1 – Enabled)
D = Speed control (0 – Disabled 1 – Enabled)
S..S = Servo speed value 0 to 15 (0 = slowest)
Servo 11 position
R21
P
P
P
P
P
P
P
P
P..P = Servo position 0 to 255 (0.5mS to 2.50mS)
Servo 11 control
R22
A
B
C
D
S
S
S
S
A = Operate (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start control (0 – Disabled 1 – Enabled)
D = Speed control (0 – Disabled 1 – Enabled)
S..S = Servo speed value 0 to 15 (0 = slowest)
Servo 12 position
R23
P
P
P
P
P
P
P
P
P..P = Servo position 0 to 255 (0.5mS to 2.50mS)
Servo 12 control
R24
A
B
C
D
S
S
S
S
A = Operate (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start control (0 – Disabled 1 – Enabled)
D = Speed control (0 – Disabled 1 – Enabled)
S..S = Servo speed value 0 to 15 (0 = slowest)
Servo 13 position
R25
P
P
P
P
P
P
P
P
P..P = Servo position 0 to 255 (0.5mS to 2.50mS)
Servo 13 control
R26
A
B
C
D
S
S
S
S
A = Operate (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start control (0 – Disabled 1 – Enabled)
D = Speed control (0 – Disabled 1 – Enabled)
S..S = Servo speed value 0 to 15 (0 = slowest)
Servo 14 position
R27
P
P
P
P
P
P
P
P
P..P = Servo position 0 to 255 (0.5mS to 2.50mS)
Servo 14 control
R28
A
B
C
D
S
S
S
S
A = Operate (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start control (0 – Disabled 1 – Enabled)
D = Speed control (0 – Disabled 1 – Enabled)
S..S = Servo speed value 0 to 15 (0 = slowest)
Servo 15 position
R29
P
P
P
P
P
P
P
P
P..P = Servo position 0 to 255 (0.5mS to 2.50mS)
Servo 15 control
R30
A
B
C
D
S
S
S
S
A = Operate (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start control (0 – Disabled 1 – Enabled)
D = Speed control (0 – Disabled 1 – Enabled)
S..S = Servo speed value 0 to 15 (0 = slowest)
Servo 16 position
R31
P
P
P
P
P
P
P
P
P..P = Servo position 0 to 255 (0.5mS to 2.50mS)
Servo 16 control
R32
A
B
C
D
S
S
S
S
A = Operate (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start control (0 – Disabled 1 – Enabled)
D = Speed control (0 – Disabled 1 – Enabled)
S..S = Servo speed value 0 to 15 (0 = slowest)
Servo 17 position
R33
P
P
P
P
P
P
P
P
P..P = Servo position 0 to 255 (0.5mS to 2.50mS)
Servo 17 control
R34
A
B
C
D
S
S
S
S
A = Operate (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start control (0 – Disabled 1 – Enabled)
D = Speed control (0 – Disabled 1 – Enabled)
S..S = Servo speed value 0 to 15 (0 = slowest)
Servo 18 position
R35
P
P
P
P
P
P
P
P
P..P = Servo position 0 to 255 (0.5mS to 2.50mS)
Servo 18 control
R36
A
B
C
D
S
S
S
S
A = Operate (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start control (0 – Disabled 1 – Enabled)
D = Speed control (0 – Disabled 1 – Enabled)
S..S = Servo speed value 0 to 15 (0 = slowest)
Servo global enable register
R37
X
X
X
X
X
X
X
X
X..X = Any value
Each control register consists of four
control bits and a four bit speed con-
trol value defined as follows:
Bit (A) 128
decimal
is the operate bit
which when set activates the servo
being controlled.
Bit (B) 64
decimal
is the reverse bit
which reverses the position value for
the servo being controlled.
Bit (C) 32
decimal
is the soft-start bit
which when set on servo first activa-
tion, see operate bit above, feeds
position pulses to the servo in a
ramping manner until position is
attained.
Bit (D) 16
decimal
is the speed control
enable bit which when set applies
the speed value 0 to 15, contained in
the four bits (SSSS) 1,2,4,8
decimal
, to
the servo being controlled.
Once all the required position &
control registers have been set a
write to the R37 (Global enable reg-
ister) must be made to activate all
the new positions.
Example.
To set the first nine servos to new positions
with servos 1 to 4 running at speed 0 and
servos 5 to 8 running at speed 5 in reverse
mode, first write:
Byte 1 (SCX18 Adr) 1110100
0
binary
Byte 2 (Register 0)
0
decimal
Byte 3 (Register 1)
30
decimal
Byte 4 (Register 2)
144
decimal
, 90
hex
Byte 5 (Register 3)
35
decimal
Byte 6 (Register 4)
144
decimal
, 90
hex
Byte 7 (Register 5)
40
decimal
Byte 8 (Register 6)
144
decimal
, 90
hex
Byte 9 (Register 7)
45
decimal
Byte 10 (Register 8) 144
decimal
, 90
hex
Byte 11 (Register 9) 127
decimal
Byte 12 (Register 10) 213
decimal
, D5
hex
Byte 13 (Register 11) 130
decimal
Byte 14 (Register 12) 213
decimal
, D5
hex
Byte 15 (Register 13) 140
decimal
Byte 16 (Register 14) 213
decimal
, D5
hex
Byte 17 (Register 15) 150
decimal
Byte 18 (Register 16) 213
decimal
, D5
hex
then to activate write:
Byte 1 (SCX18 Adr) 1110100
0
binary
Byte 2 (Register 0)
37
decimal
Byte 3 (Register 37) 0
decimal
To read the status registers a device
write then read must be undertaken
by the OOPic / I
2
C Master. The
write consists of a Start condition,
device ID (‘D’ bit cleared), register
to start read and a Stop condition.
This is followed by a read, which
consists of a Start condition, device
ID (‘D‘ bit set), followed by data
from the status register and termi-
nated with a Stop condition (see
Figure 1.1 for I
2
C read protocol).
Status registers
There are 18 registers that can be
read within the SCX18 as follows:
N
7
N
6
N
5
N
4
N
3
N
2
N
1
N
0
SCX I2C Address
1.
1
1
1
0
1
X
X
1
XX = SCX18 address
Servo 1 status
R0
A
B
C
D
0
0
0
0
A = Operation (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start (0 – Complete 1 – In-progress)
D = Movement (0 – Complete 1 – In-progress)
Servo 2 status
R1
A
B
C
D
0
0
0
0
A = Operation (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start (0 – Complete 1 – In-progress)
D = Movement (0 – Complete 1 – In-progress)
Servo 3 status
R2
A
B
C
D
0
0
0
0
A = Operation (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start (0 – Complete 1 – In-progress)
D = Movement (0 – Complete 1 – In-progress)
Servo 4 status
R3
A
B
C
D
0
0
0
0
A = Operation (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start (0 – Complete 1 – In-progress)
D = Movement (0 – Complete 1 – In-progress)
Servo 5 status
R4
A
B
C
D
0
0
0
0
A = Operation (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start (0 – Complete 1 – In-progress)
D = Movement (0 – Complete 1 – In-progress)
Servo 6 status
R5
A
B
C
D
0
0
0
0
A = Operation (0 – Servo disabled 1 – Servo enabled)
B = Reverse (0 – Servo normal 1 – Servo reversed)
C = Soft-start (0 – Complete 1 – In-progress)
D = Movement (0 – Complete 1 – In-progress)
