ST92F124R1 STMicroelectronics, ST92F124R1 Datasheet - Page 132

• Manufacturer Part Number: ST92F124R1
• Description: 8/16-bit Single Voltage Flash Mcu Family With Ram, E?? Emulated Eeprom , Can 2.0b And J1850 Blpd
• Manufacturer: STMicroelectronics

ST92F124/F150/F250 - RESET AND CLOCK CONTROL UNIT (RCCU)
Figure 63. Example of Low Power mode programming in WFI using CK_AF external clock
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9
Interrupt
CKAF_SEL ← 0
CSU_CKSEL ← 1
Interrupt Routine
CSU_CKSEL ← 1
PROGRAM FLOW
WFI_CKSEL ← 1
User’s Program
User’s Program
WFI instruction
XTSTOP ← 0
XTSTOP ← 1
LPOWFI ← 1
MX[1:0] ← 00
DX[2:0] ← 000
WFI status
WAIT
Begin
WAIT
WAIT
CK_AF selected and Xtal stopped
Wait for the Xtal
PLL is System Clock source
PLL is system clock source
Low Power Mode enabled
No code is executed until
to 1, and PLL turned ON
an interrupt is requested
Wait for the PLL to lock
Preselect Xtal stopped
Wait for the PLL to lock
Execution of user program
when CK_AF selected
CK_AF clock selected
The System Clock
and the Xtal restarts
resumes at full speed
PLL multiply factor
Interrupt serviced
the System Clock
switches to Xtal
Wait For Interrupt
Divider factor set
while CK_AF is
in WFI state
in WFI state
Reset State
automatically
set to 10
activated
to stabilise
** T
* T
1
2
= Quartz oscillator start-up time
= PLL lock-in time
F
T
Xtal
INTCLK FREQUENCY
T
2
1
**
= 4 MHz
*
20 MHz
2 MHz
20 MHz
2 MHz
F
CK_AF