NEC PD754244 Manuel D’Utilisation

User’s Manual  U10676EJ3V0UM

BTM is a 4-bit register that controls the operation of the basic interval timer (BT).

This register is set by a 4-bit memory manipulation instruction.

Bit 3 of BT can be manipulated by a bit manipulation instruction.

To set the interrupt generation interval of the 

µPD754244 to 1.37 ms (at f

X

 = 6.0 MHz)

SEL

MB15

; or CLR1 MBE

CLR1

WDTM

MOV

A, #1111B

MOV

BTM,A

; BTM 

← 1111B

Note It is 1.95 ms when the 

µPD754244 is operating at f

X

 = 4.19 MHz.

In the case of 

µPD754144, it is fixed to 2

9

/f

CC

 (512 

µs at 1.0 MHz).

When bit 3 of this register is set to “1”, the contents of BT are cleared, and at the same time, the basic interval

timer/watchdog timer interrupt request flag (IRQBT) is cleared (the basic interval timer/watchdog timer is started).

When the RESET signal is asserted, the contents of this register are cleared to “0”, and the generation interval

time of the interrupt request signal is set to the longest value.