tmp89fm42k TOSHIBA Semiconductor CORPORATION, tmp89fm42k Datasheet - Page 40

• Manufacturer Part Number: tmp89fm42k
• Description: 8 Bit Microcontroller Tlcs-870/c1 Series
• Manufacturer: TOSHIBA Semiconductor CORPORATION

2.3
System clock controller
RA000
PINTWUC:
Example: Setting ports P00 and P01 as oscillation pins and switching the high-frequency reference clock from fosc to fc
LD
LD
SET
SET
SET
:
SET
NOP
NOP
CLR
RETI
(warm-up time: approx. 300 μs at fc = 8 MHz)
(WUCCR), 0y00000001
(WUCDR), 0x26
(EIRL).4
(P0FC).0
(SYSCR2). 6
:
(SYSCR1). 3
(SYSCR2). 7
Page 22
;WUCCR<WUCDIV>←"00" (No division)
;WUCCR<WUCSEL>←"01" (Selects fc as the source clock)
;Sets the warm-up time
;(Determine the time depending on the oscillator characteristics)
;300μs / 8 μs =37.5 round up to 0x26
;Enables INTWUC interrupts
;P0FC0←"1" (Set P00 and P01 as oscillation pins)
;SYSCR2<XTEN>←"1"
;(Starts the external high-frequency clock oscillation and starts the
;warm-up counter)
;SYSCR1<OSCSEL>←"1"
;(Switches the high-frequency reference clock from fosc to fc)
;Waits for 2 machine cycles
;Waits for 2 machine cycles
;SYSCR2<OSCEN>←"0" (Stops fosc)
TMP89FM42K