AN1139 STMicroelectronics, AN1139 Datasheet - Page 62

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

AN1139 APPLICATION NOTE
31. Get the PHASE with a most frequent lowest time. (PHASE is a position where the
rotor is suppose to be).
STARTING
32. ISNS - Reg# 8.3 [1 = preset spindle inductive start-up sense circuits]. Set to 0.
33. PWM/LIN - Reg#2.6 [1 = pwm current control, 0 = linear ]. Set as required.
34. IL1/IL0 - Reg#8.4.5 [Phase Detection Current Threshold]. Set as required.
35. R_SEQ - Reg#2.2 [1 = reset sequencer to phase 1]. Set to 1.
36. R_SEQ - Reg#2.2 [1 = reset sequencer to phase 1]. Set to 0.
37. If PHASE=1 go to Step # 41.
38. INCRE_SEQ - Reg#2.0 [transition 0 to 1 increments spindle sequencer]. Set to 1.
39. INCRE_SEQ - Reg#2.0 [transition 0 to 1 increments spindle sequencer]. Set to 0.
40. Repeat from step # 38 for PHASE minus 1 times. (Example: if PHASE=3 repeat 2
times. This is to bring the Sequencer to the same phase of the Rotor).
41. SPIN_EN - Reg#2.4 [1 = enable spindle outputs, 0 = disable]. Set to 1.
42. START_UP - Reg#2.1 [1 = internal start-up, 0 = external]. Set to 1.
43. Wait 10mS (this time may vary).
44. START_UP - Reg#2.1 [1 = internal start-up, 0 = external]. Set to 0. (Steps # 42, #43, #44 are to charge
the external Compensation Capacitor if LINEAR mode is used. If PWM mode is used, they may be skipped).
45. INCRE_SEQ - Reg#2.0 [transition 0 to 1 increments spindle sequencer]. Set to 1.
46. INCRE_SEQ - Reg#2.0 [transition 0 to 1 increments spindle sequencer]. Set to 0.
47. Wait 20mS (this time may vary).
48. INCRE_SEQ - Reg#2.0 [transition 0 to 1 increments spindle sequencer]. Set to 1.
49. INCRE_SEQ - Reg#2.0 [transition 0 to 1 increments spindle sequencer]. Set to 0.
50. Wait 3mS (this time may vary).
51. START_UP - Reg#2.1 [1 = internal start-up, 0 = external]. Set to 1.
52. Check for desired Speed.
53. SD0...SD3 - Reg#3.7.6.5.4. [commutation delay]. Set as required
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