AN1139 STMicroelectronics, AN1139 Datasheet - Page 61

• Manufacturer Part Number: AN1139
• Description: L6254 - L6268 - L6269 12V DISK DRIVE POWER COMBO IC
• Manufacturer: STMicroelectronics

8.3
Following is the Step by Step approch to perform the Inductive Sense Start-Up Option. The device has to be
programmed exactely in the order described. A flow Chart of this Start-Up is available in Figure #4 inside chaper
4 (Spindle Circuits) in section 4.1.2.3 (Inductive Sense).
GENERAL SETUP
1.
2.
3.
4.
5.
6.
7.
8.
9.
10. ICP - Reg#8.1 [1 = 25 A, 0 = 100 A]. Set as required.
11. PWM/LIN - Reg#2.6 [1 = pwm current control, 0 = linear ]. Set to 1.
12. FLL, Fine and Coarse Counters - Regs# 4,5,6. Set as required.
13. ISNS - Reg#8.3 [1 = presets spindle inductive start-up sense circuits]. Set to 1.
15. RUN - Reg#2.3 [1 = start internal Align&Go, 0 = reset logic]. Set to 1.
PHASE DETECTION
16. Set TRIAL counter to 1.
17. Set PHASE counter to 1.
18. Preset a COUNTER with at least 500nS resolution.
19. Store Initilal Time Period.
20. SPIN_EN - Reg#2.4 [1 = enable spindle output, 0 = disable]. Set to 1.
21. Start COUNTER.
22. Monitor at the same time, the FCOM pin #1 output for transition from low level
23. If COUNTER is greater than 50mS, set to 0 SPIN_EN Reg#2.4 and lower the threshold
24. If the Threshold is reached (FCOM is at high level), stop COUNTER and reset to 0 SPIN_EN - Reg#2.4 bit.
25. If COUNTER time is shortest than the previous one, store Time and PHASE.
26. INCRE_SEQ - Reg#2.0 [transition 0 to 1 increments spindle sequencer]. Set to 1.
27. INCRE_SEQ - Reg#2.0 [transition 0 to 1 increments spindle sequencer]. Set to 0.
28. Increment PHASE and reapet from step #20 until PHASE=6.
29. Store PHASE with lowest time.
30. Increment TRIAL and repeat from step # 19 until TRIAL=5.
INCRE_SEQ - Reg#2.0 [transition 0 to 1 increments spindle sequencer ]. Set to 0.
START_UP - Reg#2.1 [1 = internal start-up, 0 = external]. Set to 0.
R_SEQ - Reg#2.2 [1 = reset sequencer to phase 1]. Set to 1.
R_SEQ - Reg#2.2 [1 = reset sequencer to phase 1]. Set to 0.
RUN - Reg#2.3 [1 = start internal Align&Go start-up, 0 = reset logic]. Set to 0.
SPIN_EN - Reg#2.4 [1 = enable spindle outputs, 0 = disable]. Set to 0.
EXT/INT - Reg#2.7 [1 = external spindle feedback ,0 = internal]. Set to 1.
MEC/ELEC - Reg#2.5 [1 = electrical cycle for FLL, 0 = mechanical]. Set as required.
8_12_POLE - Reg#3.3 [1 = 8 pole, 0 = 12 pole]. Set as required.
(0 volt) to high level (5 volt) and the COUNTER for the end of count (>50mS).
according to step #14. Then restart from step # 16.
INDUCTIVE SENSE START-UP STEP BY STEP
AN1139 APPLICATION NOTE
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