UPD75518 NEC, UPD75518 Datasheet - Page 64

• Manufacturer Part Number: UPD75518
• Description: 4 BIT SINGLE-CHIP MICROCOMPUTER
• Manufacturer: NEC

64
(3) Basic interval timer mode register (BTM)
BTM is a 4-bit register that controls operation of the basic interval timer.
The BTM contents are set by using a 4-bit memory manipulation instruction.
Bit 3 can be independently set using a bit manipulation instruction.
When bit 3 is set to 1, the contents of the basic interval timer are cleared, and the basic interval timer
interrupt request flag (IRQBT) is also cleared (to start the basic interval timer).
The generation of a RESET signal clears the contents to 0, and the longest interrupt request signal
generation interval time is set.
Examples 1. Set the interrupt generation interval to 1.95 ms (4.19 MHz).
2. Clear BT and IRQBT (application of the watchdog timer)
SEL
MOV
MOV
SEL
SET1
MB15
A, #1111B
BTM, A
MB15
BTM.3
; or CLR1 MBE
; BTM
; or CLR1 MBE
; Set bit 3 of BTM to 1
1111B
PD75518(A)