SLFS040

– DECEMBER 1993

POST OFFICE BOX 655303

DALLAS, TEXAS 75265

18

PRINCIPLES OF OPERATION

Count_Enable

Fspn

Fref

Up

Count_Clear

Speed Up

Slow Down

Down

Speed

Detect

Kt

Js

Motor

Ispindle

VSPNCOMP

/12 or /18

1440 Hz @ Fspn = 3600 RPM

Fspn

Fref

Up

Down

Charge

Pump

/2

/8

Padv

MTRCLK

Count_Enable

Count_Clear

GA

Time-Difference

Detector

8-Pole Motor

(/R) + 1

0<R<2047

SPNCOMP

NOTE: Area within dotted line is internal to the device

Cspn2

Cspn1

Rspn

SPNSW

SPNMODE

Figure 7. Spindle-Control Loop Block Diagram and Timing Waveforms

serial port

The TLS2205 serial port is designed to receive 16-bit data in three-wire serial format and distribute the data to

internal data and control ports. The serial-port interface is designed to be compatible with the Texas Instruments

TMS320C2x digital signal processor (DSP) family or standard 8- or 16-bit microprocessors. Data can be

transmitted in either 8- or 16-bit format. The data is sent MSB first for the 16-bit word. The first four MSBs

determine the port address. The other 12 bits are used for data or port control functions. The first two MSBs must

both be 0 to select the device. The received data is routed to one of three internal 12-bit register ports. Port A

controls the VCM DAC and gain range of eight data bits with four gain ranges. Port B is used to set the spindle

reference counter. Port C is used for system controls.