ST10F272B_12 STMICROELECTRONICS [STMicroelectronics], ST10F272B_12 Datasheet - Page 102

• Manufacturer Part Number: ST10F272B_12
• Description: 16-bit MCU with 256 Kbyte Flash memory and 12/20 Kbyte RAM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

System reset
20.7
102/188
Figure 28. SW / WDT bidirectional RESET (EA=0) followed by a HW RESET
Reset circuitry
Internal reset circuitry is described in
resistor of 50kΩ to 250kΩ (The minimum reset time must be calculated using the lowest
value).
It also provides a programmable (BDRSTEN bit of SYSCON register) pull-down to output
internal reset state signal (synchronous reset, watchdog timer reset or software reset).
This bidirectional reset function is useful in applications where external devices require a
reset signal but cannot be connected to RSTOUT pin.
This is the case of an external memory running codes before EINIT (end of initialization)
instruction is executed. RSTOUT pin is pulled high only when EINIT is executed.
The RPD pin provides an internal weak pull-down resistor which discharges external
capacitor at a typical rate of 200μA. If bit PWDCFG of SYSCON register is set, an internal
pull-up resistor is activated at the end of the reset sequence. This pull-up will charge any
capacitor connected on RPD pin.
The simplest way to reset the ST10F272 is to insert a capacitor C1 between RSTIN pin and
V
RPD pin and V
50kΩ to 250kΩ (the minimum reset time must be determined by the lowest value). Select C1
that produce a sufficient discharge time to permit the internal or external oscillator and / or
internal PLL and the on-chip voltage regulator to stabilize.
SS
, and a capacitor between RPD pin and V
DD
. The input RSTIN provides an internal pull-up device equalling a resistor of
Doc ID 11917 Rev 3
Figure
31. The RSTIN pin provides an internal pull-up
SS
(C0) with a pull-up resistor R0 between
ST10F272B/ST10F272E