NEC PD754144 - Manual (Page 177)

CHAPTER 6 PERIPHERAL HARDWARE FUNCTION
177 User’s Manual U10676EJ3V0UM
(5) Note on application of carrier generator (on starting)
When the carrier clock is generated, after the timer has been started (by setting bit 3 of TM2 to “1”), the high-
level period of the initial carrier clock may deviate by up to one clock of the count pulse (CP) (up to two clocks
of CP if the frequency of CP is higher than one machine cycle) from the value calculated by the expression
(contents of modulo register + 1)
× resolution (for details, refer to (1) Error when timer starts).
To output a carrier as the initial code, if the timer is started (by setting bit 3 of TM2 to “1”) after the no return
zero flag (NRZ) has been set to “1”, the high-level period of the initial carrier clock includes the possibility of
an error that may occur when the timer is started.
0 1 0 1 0
0 1
PTO2
TOUT F/F
NRZ
SET1 NRZ
SET1 TM2.3 Error on start of
timer is included
Therefore, to output a carrier as the initial code, set NRZ to “1” after the timer has been started (by setting
bit 3 of TM2 to “1”).
0 1 0 1 0
0 1
Clock
TOUT F/F
NRZ
SET1 NRZ
SET1 TM2.3 Error on start of
timer is included
PTO2