
15. Three-Phase Motor Control Timer Function
Figure 15.12
Triangular Wave Modulation Operation (Three-Phase Mode 1)(INV00 = 0)
r
q
Dead time
DUB0 = 0
m
Triangular Waveform as a Carrier Wave (Three-phase mode 1) (INV00 = 0)
Carrier wave
TB2S bit in the
TABSR register
Signal wave
Timer B2
Timer A4 start trigger signal(1)
TA4 register
Reload register(1)
n
p
n
p
q
Timer A4 one-shot pulse(1)
INV14 bit in
INVC1 register = 0
("L" active)
Dead time
Transfer values to the three-phase shift register from registers IDB0 and IDB1
Rewrite registers IDB0 and IDB1
U-phase output signal(1)
U-phase
INV14 bit in
INVC1 register = 1
("H" active)
U-phase
IR bit in the TB2IC register
m
nn
pp
qq
DU0 = 1
DU1 = 0
DUB1 = 1
DUB1 = 0
DUB0 = 0
DU0 = 1
DU1 = 1
Set to 0 by an interrupt request acknowledgement or by program
Timer A1 reload control signal
TA41 register
m
n
p
r
NOTE:
1. Internal signals. See Three-Phase Motor Control Timer Function Block Diagram.
The above applies under the following conditions:
- INVC0 register: INV00 bit = 0 (ICTB2 counter is incremented by 1 at the rising edge of the timer A1 reload control signal)
INV01 bit = 1 (Selected by the INV00 bit)
INV02 bit = 1 (Three-phase control timer function used)
INV03 bit = 1 (Three-phase control timer output enabled)
INV06 bit = 0 (Triangular wave modulation mode)
- INVC1 register: INV10 bit = 0 (Timer B2 underflows)
INV11 bit = 1 (Three-phase mode 1)
INV15 bit = 0 (Dead time enabled)
INV16 bit = 1 (Rising edge of the three-phase output shift register (U-, V-, W-phase)
- ICTB2 register = 01h (First timer B2 interrupt occurs when timer B2 underflows for the first time, and the subsequent
interrupts occur every second timer B2 underflow.)
The following shows examples to change PWM output levels.
- Default value of the timer: TA41 = m, TA4 = m (Registers TA4 and TA41 are changed whenever the timer B2 interrupt is generated.)
First time TA41 = n, TA4 = n, second time TA41 = p, TA4 = p
- Default value of the registers IDB0 and IDB1: DU0 = 1, DUB0 = 0, DU1 = 0, and DUB1 = 1
They are changed to DU0 = 1, DUB0 = 0, DU1 = 1, and DUB1 = 0 when the third timer B2 interrupt is generated.