ST72141K2 datasheet(53/132 Pages) STMICROELECTRONICS

53 / 132 page

ST72141K

53/132

MOTOR CONTROLLER (Cont’d)

8.1.4.2 Delay Manager

Figure 33. Overview of MTIM Timer

This part of the MTC contains all the time-related

functions, its architecture is based on an 8-bit shift

left/shift right timer shown in Figure 33. The MTIM

timer includes:

– An auto-updated prescaler

– A capture/compare register for software demag-

netization simulation (MDREG)

– Two cascaded capture register (MZREG and

MZPRV) for storing the times between two con-

secutive BEMF zero crossings (Z events)

– An 8x8 bit multiplier for auto computing the next

commutation time

– One compare register for phase commutation

generation (MCOMP)

The MTIM timer module can work in two main

modes. In switched mode the user must process

the step duration and commutation time by soft-

ware, in autoswitched mode the commutation ac-

tion is performed automatically depending on the

rotor position information and register contents.

Table 16. Switched and Autoswitched Modes

Switched Mode

This feature allows the motor to be run step-by-

step. This is useful when the rotor speed is still too

low to generate a BEMF. It can also run other

kinds of motor without BEMF generation such as

induction motors or switch reluctance motors. This

mode can also be used for autoswitching with all

computation for the next commutation time done

by software (hardware multiplier not used) and us-

ing the powerful interrupt set of the peripheral.

In this mode, the step time is directly written by

software in the commutation compare register

MCOMP. When the MTIM timer reaches this value

a commutation occurs (C event) and the MTIM

timer is reset.

8-bit Up Counter MTIM§

MZREG [Zn]

MZPRV [Zn-1]

MDREG [Dn]

Compare

MCOMP [Cn+1]

DS,H

Tratio

SDM bit

clr

SWA bit

§ = Register updated on R event

To interrupt generator

MCRA register

MCRB register

SWA

bit

Commutation Type

MCOMP User

access

Switched mode

Read/Write

Autoswitched mode

Read only

ST72141K2 データシート(PDF) 53 Page - STMicroelectronics

ST72141K2 データシート(HTML) 53 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

データシートダウンロード