Basic Interval Timer Mode Register (Btm); Basic Interval Timer Mode Register Format - NEC PD75402A User Manual

5.4.2 Basic Intercal Timer Mode Register (BTM)
BTM is a 4-bit register which controls the operation of the basic interval timer.
BTM is set by a 4-bit memory handling instruction. Bit operations are not possible.
Example To set the interrupt generation interval to 1.95 ms (4.19 MHz).
MOV
MOV
When bit 3 is set (1), the contents of the basic interval timer are cleared and at the same time the basic interval
timer interrupt request flag (IRQBT) is also cleared (start of basic interval timer).
With a RESET input, BTM contents are cleared to zero and the interrupt request signal generation interval is set
to the maximum length.
3 2 1
Address
F85H BTM3 BTM3 1
Note Ensure that 1 is written to bits 1 and 0.
CHAPTER 5. PERIPHERAL HARDWARE FUNCTIONS
A, #1111B
BTM. A
Fig. 5-22 Basic Interval Timer Mode Register Format
0 Symbol
1 BTM
Input Clock Specification
0 f /2
XX
1 f /2
XX
( ) : Values when f
Basic interval timer start control bit
Basic interval timer is started by writeng "1"* (counter
and interrupt request flay are interrupt request flag are
cleared). Automatically reset (0) when operation is started.
* Ensure that the write is performed by a 4-bit write instruction.
; BTM 1111B
Interrupt Interval
(
Wait Time when Standby
Mode is Released)
9 17
(8.18 kHz) 2 /f
5 13
(131 kHz) 2 /f
= 4.19 MHz
XX
)
(31.3 ms)
XX
(19.5 ms)
XX
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