SAME SKY | SERIES: AMT22 | DESCRIPTION: MODULAR ABSOLUTE ENCODER

date 09/12/2024 | page 2 of 9

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ENVIRONMENTAL

parameter

conditions/description

min

typ

max

units

operating temperature

-40

105

°C

humidity

non-condensing

85

%

vibration

10~500 Hz, 5 minute sweep, 2 hours on each XYZ

5

G

shock

3 pulses, 6 ms, 3 on each XYZ

200

G

RoHS

yes

SERIAL INTERFACE

parameter

conditions/description

min

typ

max

units

protocol

Serial Peripheral Interface Mode 0

frame size

8

bit

data rate

2

MHz

transceiver

SPI driven by PIC18F14K223

T

CLK

data shifted to output buffer4

2.5

µs

T

B

time between bytes

2.5

µs

T

CS

time between reads

40

µs

T

R

time before CS can be released

3

µs

Notes:

3. See Microchip documentation for more details.

4. This is the time it takes to load the most current position into the SPI buffer which prevents multiple read/response commands from being required.

1

K1

K0

D14

D13

D12

D11

D10

D9

CHIP SELECT

SCLK

MISO

1

First Command Char

T

CS

C7

C6

C5

C4

MOSI

23

4

5

6

7

8

C3

C2

C1

C0

D8

D7

D6

D5

D4

D3

D2

D1

C7

C6

C5

C4

C3

C2

C1

C1

T

CLK

T

B

23

4

5

6

7

8

Second Command Char

T

R

Figure 1

Timing Waveform

Values K1 and K0 in the response are checkbits. The checkbits are odd parity over the odd and even bits in the position response shown in

the equation below. The checkbits are not part of the position, but are used to verify its validity. The lower 14 bits are the encoder position.

Example:

Full response: 0x61AB

14-bit position: 0x21AB (8619 decimal)

Checkbit Formula

Odd: K1 = !(H5^H3^H1^L7^L5^L3^L1)

Even: K0 = !(H4^H2^H0^L6^L4^L2^L0)

From the above response 0x61AB:

Odd: 0 = !(1^0^0^1^1^1^1) = correct

Even: 1 = !(0^0^1^0^0^0^1) = correct

For 12-bit applications L0 and L1 are always 0. Because the low two bits are 0, 12-bit data will need right-shifted two bits. The checkbit

calculation remains the same and unaffected.

Additional Resources: Product Page | 3D Model