AN2841 Freescale Semiconductor / Motorola, AN2841 Datasheet - Page 10

• Manufacturer Part Number: AN2841
• Description: Using the Hall Decoder (HD) eTPU Function
• Manufacturer: Freescale Semiconductor / Motorola

C Level API for Function
3.3
Like all eTPU functions, the HD function performance in an application is to some extent dependent upon
the service time (latency) of other active eTPU channels. This is due to the operational nature of the
scheduler.
The influence of the HD function on the overall eTPU performance can be expressed by the following
parameter:
Table 1
commutation processing. Where commutation processing is enabled, the value also covers the processing
of two commutation commands performed by the PWMC function.
The performance is influenced by compiler efficiency. The above numbers, measured on the code
compiled by eTPU compiler version 1.0.115.990, are given for guidance only and are subject to change.
For up to date information, refer to the information provided in the particular eTPU function set release
available from Freescale.
4
The following routines provide the application developer easy access to the HD function. Use of these
functions eliminates the need to directly control the eTPU registers. There are 24 functions added to the
application programming interface (API). The routines can be found in the etpu_hd.h and
etpu_hd.c files, which should be included in the link file along with the top level development file(s).
These routines will be described in order and are listed below:
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maximum eTPU busy-time per sector
This value determines the eTPU time necessary for processing one transition of a Hall sensor
signal.
Initialization Functions:
lists the maximum eTPU busy-times per sector in eTPU cycles that depend on the mode of
Performance
C Level API for Function
int32_t fs_etpu_hd_init_1ph(
Commutation processing disabled
Commutation processing Mode
Commutation processing enabled
Table 1. Maximum eTPU Busy-Time per Sector
etpu_hd_phase_commut_cmds_t *phaseA_commut_cmds)
Using the Hall Decoder (HD) eTPU Function, Rev. 0
uint8_t channel_phaseA,
uint8_t timer,
uint8_t direction,
uint8_t PWMM_chan,
Maximum eTPU busy-time per
[eTPU cycles]
sector
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