tmp88f846ug TOSHIBA Semiconductor CORPORATION, tmp88f846ug Datasheet - Page 147

• Manufacturer Part Number: tmp88f846ug
• Description: 8 Bit Microcontroller
• Manufacturer: TOSHIBA Semiconductor CORPORATION

14.6.1 Electrical Angle Timer and Waveform Arithmetic Circuit
(EDSET). The Electrical Angle Timer counts 360 degrees of electrical angle in the range of 0 to 383 (17FH)
and is cleared to 0 upon reaching 383. In this way, it is possible to obtain the electrical angle of the frequency
proportional to the value set by the Period Set Register. The period with which to count up can be corrected by
using the Period Correction Register, allowing for fine adjustment of the frequency. The electrical angles
counted by the Electrical Angle Timer are presented to the Waveform Arithmetic Circuit. An electrical angle
timer interrupt signal is generated each time the Electrical Angle Timer finishes counting.
on the electrical angle data received from the Electrical Angle Timer. This sine wave data is multiplied by the
value of the Voltage Amplitude Register. For 2-phase modulation, the product obtained by this multiplication is
presented to the waveform synthesis circuit. For 3-phase modulation, waveform data is further calculated
based on the product of multiplication and the electrical angle data and the value of the PWM Period Register.
The calculation is performed each time the Electrical Angle Timer finishes counting or when a value is set in
the Electrical Angle Register, and the calculation results consisting of the U phase, the V phase (+120 degrees),
and the W phase (+240 degrees) are sequentially presented to the PWM waveform output circuit. The sine
wave data table is stored in the RAM and requires initialization.
The Electrical Angle Timer finishes counting upon reaching the value set by the Period Set Register
The Waveform Arithmetic Circuit has a sine wave data table, which is used to extract sine wave data based
Note 1: The value set in the Period Set Register (EDSET Register EDT bits) must be equal to or greater than 010H.
Note 2: The sine wave data that is read consists of the U phase, the V phase whose electrical angle is +120
Note 3: If a period corresponding to an electrical angle of one degree is shorter than the required calculation time,
• To correct the period, set the number of times ‘n’ to be corrected in the Period Correction Register
• Because the electrical angle counter (ELDEG) can be accessed even while the Electrical Angle Timer
• The Electrical Angle Capture EDCAP captures the electrical angle value from the Electrical Angle
• When the waveform calculation function is enabled, waveform calculation is performed each time the
• The calculation is performed in 35 machine cycle of execution time, or 7 µs (at 20 MHz).
• When transfer of calculation result to the CMP Registers is enabled (EDCRA<RWREN>), the calcula-
• The calculated results can be modified and the modified data can be set in the CMPU to W Registers in
• To initialize the entire RAM data of the sine wave data table, set the addresses at which to set, sequen-
(EDSET Register F to C bits). The period is corrected by adding 1 to electrical angle counts 16 for ‘n’
times. For example, when a value 3 is set in the Period Correction Register, the period for 13 times out
of electrical angle counts 16 is the value “mH” set in the Period Set Register, and that for 3 times is “m
+ 1H”. (Correction is made almost at equal intervals.)
is operating, the electrical angles can be corrected during operation.
Counter at the time the position is detected.
electrical angle counter (ELDEG) are accessed for write or the Electrical Angle Timer finishes count-
ing.
tion results are transferred to the CMPU to W Registers. (This applies only when the waveform calcu-
lation function is enabled with the EDCRA<CALCEN>.) The CMPU to W Registers are disabled
against write while the transfer remains enabled. The calculation results can be read from the CMPU to
W Registers while the waveform calculation function remains enabled.
software. This makes it possible to output any desired waveform other than sine waves.
If a transfer (EDCRA register bit 2) of the calculated results to the CMP register is disabled, read-
accessing the CMPU to W registers can read the calculated results. (Before read-accessing these regis-
ters, make sure that the calculation is completed.)
tially from 000H to 17FH, in the ELDEG Register, and write waveform data to the WFMDR Register
each time. Make sure the Waveform Arithmetic Circuit is disabled when writing this data.
Any value smaller than this is assumed to be 010H.
degrees relative to the U phase, and the W phase whose electrical angle is +240 degrees relative to the U
phase.
the previously calculated results are used.
Page 137
TMP88F846UG