STEVAL-SCM001V1 STMicroelectronics, STEVAL-SCM001V1 Datasheet - Page 27
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STEVAL-SCM001V1
Manufacturer Part Number
STEVAL-SCM001V1
Description
KIT DEMO DONGLE RTC M41T62/ST7
Manufacturer
STMicroelectronics
Datasheets
1.M41T62Q6F.pdf
(43 pages)
2.STEVAL-SCM001V1.pdf
(4 pages)
3.STEVAL-SCM001V1.pdf
(4 pages)
Specifications of STEVAL-SCM001V1
Design Resources
STEVAL-SCM001V1 Gerber Files STEVAL-SCM001V1/RTC Schematic
Main Purpose
Timing, ARM7 based RTC USB Dongle
Embedded
Yes, MCU, 8-Bit
Utilized Ic / Part
M41T62, ST72F651
Primary Attributes
RTC (Real-Time Clock) and Mass Storage Capabilities
Secondary Attributes
Graphical User Interface, USB Interface
Silicon Manufacturer
ST Micro
Silicon Core Number
M41T62 And ST72651AR6
Kit Application Type
Clock & Timing
Application Sub Type
RTC Dongle
Kit Contents
Board CD Docs
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
497-5684
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
STEVAL-SCM001V1
Manufacturer:
STMicroelectronics
Quantity:
135
M41T62/63/64/65
3.4
Note:
Note:
3.5
Note:
Watchdog timer
The watchdog timer can be used to detect an out-of-control microprocessor. The user
programs the watchdog timer by setting the desired amount of time-out into the watchdog
register, address 09h.
Bits BMB4-BMB0 store a binary multiplier and the three bits RB2-RB0 select the resolution
where:
000=1/16 second (16 Hz);
001=1/4 second (4 Hz);
010=1 second (1 Hz);
011=4 seconds (1/4 Hz); and
100 = 1 minute (1/60 Hz).
Invalid combinations (101, 110, and 111) will NOT enable a watchdog time-out. Setting
BMB4-BMB0 = 00000 with any combination of RB2-RB0, other than 000, will result in an
immediate watchdog time-out.
The amount of time-out is then determined to be the multiplication of the five-bit multiplier
value with the resolution. (For example: writing 00001110 in the watchdog register = 3*1 or 3
seconds). If the processor does not reset the timer within the specified period, the M41T6x
sets the WDF (watchdog flag) and generates an interrupt on the IRQ pin (M41T62), or a
watchdog output pulse (M41T63 and M41T65 only) on the WDO pin. The watchdog timer
can only be reset by having the microprocessor perform a WRITE of the watchdog register.
The time-out period then starts over.
Should the watchdog timer time-out, any value may be written to the watchdog register in
order to clear the IRQ pin. A value of 00h will disable the watchdog function until it is again
programmed to a new value. A READ of the flags register will reset the watchdog flag (bit
D7; register 0Fh). The watchdog function is automatically disabled upon power-up, and the
watchdog register is cleared.
A WRITE to any clock register will restart the watchdog timer.
Watchdog output (WDO - M41T63/65 only)
If the processor does not reset the watchdog timer within the specified period, the watchdog
output (WDO) will pulse low for t
connected to the reset input of the processor in order to generate a processor reset. After a
watchdog time-out occurs, the timer will remain disabled until such time as a new
countdown value is written into the watchdog register.
The crystal oscillator must be running for the WDO pulse to be available.
The WDO output is an N-channel, open drain output driver (with I
on page
33).
Doc ID 10397 Rev 15
rec
(see
Table 18 on page
35). This output may be
OL
as specified in
Clock operation
Table 14
27/43