ST92T141K4M6 STMicroelectronics, ST92T141K4M6 Datasheet - Page 57

• Manufacturer Part Number: ST92T141K4M6
• Description: Microcontrollers (MCU) OTP EPROM 16K SPI
• Manufacturer: STMicroelectronics

Specifications of ST92T141K4M6

• Data Bus Width: 8 bit, 16 bit
• Program Memory Type: EPROM
• Program Memory Size: 16 KB
• Data Ram Size: 512 B
• Interface Type: SPI
• Maximum Clock Frequency: 25 MHz
• Number Of Programmable I/os: 15
• Number Of Timers: 2
• Operating Supply Voltage: 4.5 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SO-34
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit, 6 Channel
• Lead Free Status / Rohs Status: No

WAKE-UP / INTERRUPT LINES MANAGEMENT UNIT (Cont’d)
2. Interrupt requests to CPU are enabled: in this
If the MCU really exits from STOP Mode, the
RCCU EX_STP bit is still set and must be reset by
software. Otherwise, if an Interrupt/DMA request
was acknowledged during the STOP bit setting se-
quence, the RCCU EX_STP bit is reset. This
means that the MCU has filtered the STOP Mode
entry request.
The WKUP-INT bit can be used by an interrupt
routine to detect and to distinguish events coming
from Interrupt Mode or from Wake-up Mode, allow-
ing the code to execute different procedures.
To exit STOP mode, it is sufficient that one of the
16 wake-up lines (not masked) generates an
event: the clock restarts after the delay needed for
the oscillator to restart.
Note: After exiting from STOP Mode, the software
can successfully reset the pending bits (edge sen-
sitive), even though the corresponding wake-up
line is still active (high or low, depending on the
Trigger Event register programming); the user
must poll the external pin status to detect and dis-
tinguish a short event from a long one (for example
keyboard input with keystrokes of varying length).
3.12.4 Programming Considerations
The following paragraphs give some guidelines for
designing an application program.
case the ST9 will not enter STOP mode and the
interrupt service routine will be executed. The
status of STOP and EX_STP bits will be again:
The interrupt service routine can determine why
the ST9 did not enter STOP mode by polling
the pending bits of the external lines (at least
one must be at 1).
STOP = 0, EX_STP = 0
3.12.4.1 Procedure for Entering/Exiting STOP
mode
1. Program the polarity of the trigger event of
2. Check that at least one mask bit (registers
3. Reset at least the unmasked pending bits: this
4. Select the interrupt source of the INTD1 chan-
5. To generate an interrupt on channel INTD1, bits
6. Reset the STOP bit in register WUCTRL and
7. To enter STOP mode, write the sequence 1, 0,
8. The code to be executed just after the STOP
9. Poll the wake-up pending bits to determine
10.Clear the wake-up pending bit that was set.
external wake-up lines by writing registers
WUTRH and WUTRL.
WUMRH, WUMRL) is equal to 1 (so at least
one external wake-up line is not masked).
allows a rising edge to be generated on the
INTD1 channel when the trigger event occurs
(an interrupt on channel INTD1 is recognized
when a rising edge occurs).
nel (see description of ID1S bit in the WUCTRL
register) and set the WKUP-INT bit.
EITR.1 (R242.7, Page 0) and EIMR.1 (R244.7,
Page 0) must be set and bit EIPR.7 must be
reset. Bits 7 and 6 of register R245, Page 0
must be written with the desired priority level for
interrupt channel INTD1.
the EX_STP bit in the CLK_FLAG register
(R242.7, Page 55). Refer to the RCCU chapter.
1 to the STOP bit in the WUCTRL register with
three consecutive write operations.
sequence must check the status of the STOP
and RCCU EX_STP bits to determine if the ST9
entered STOP mode or not (See “Wake-up
Mode Selection” on page 56. for details). If the
ST9 did not enter in STOP mode it is necessary
to reloop the procedure from the beginning, oth-
erwise the procedure continues from next point.
which wake-up line caused the exit from STOP
mode.
ST92141 - INTERRUPTS
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