参数资料
型号: ST6228C
英文描述: 8-BIT MICROCONTROLLER ( MCU ) WITH OTP. ROM. FASTR A/D CONVERTER. 8-BIT AUTO-RELOAD TIMER. UART. OSG. SAFE RESET AND 28 PINS
中文描述: 8位微控制器(MCU)的与检察官办公室。光盘。 FASTR的A / D转换器。 8位自动重加载定时器。 UART的。业务支助。安全复位和28个引脚
文件页数: 23/84页
文件大小: 969K
代理商: ST6228C
23/84
ST62T28C/E28C
3.3 DIGITAL WATCHDOG
The digital Watchdog consists of a reloadable
downcounter timer which can be used to provide
controlled recovery from software upsets.
The Watchdog circuit generates a Reset when the
downcounter reaches zero. User software can
prevent this reset by reloading the counter, and
should therefore be written so that the counter is
regularly reloaded while the user program runs
correctly. In the event of a software mishap (usual-
ly caused by externally generated interference),
the user program will no longer behave in its usual
fashion and the timer register will thus not be re-
loaded periodically. Consequently the timer will
decrement down to 00h and reset the MCU. In or-
der to maximise the effectiveness of the Watchdog
function, user software must be written with this
concept in mind.
Watchdog behaviour is governed by two options,
known as “WATCHDOG ACTIVATION” (i.e.
HARDWARE or SOFTWARE) and “EXTERNAL
STOP MODE CONTROL” (see
Table 7
).
In the SOFTWARE option, the Watchdog is disa-
bled until bit C of the DWDR register has been set.
When the Watchdog is disabled, low power Stop
mode is available. Once activated, the Watchdog
cannot be disabled, except by resetting the MCU.
In the HARDWARE option, the Watchdog is per-
manently enabled. Since the oscillator will run con-
tinuously, low power mode is not available. The
STOP instruction is interpreted as a WAIT instruc-
tion, and the Watchdog continues to countdown.
However, when the EXTERNAL STOP MODE
CONTROL option has been selected low power
consumption may be achieved in Stop Mode.
Execution of the STOP instruction is then gov-
erned by a secondary function associated with the
NMI pin. If a STOP instruction is encountered
when the NMI pin is low, it is interpreted as WAIT,
as described above. If, however, the STOP in-
struction is encountered when the NMI pin is high,
the Watchdog counter is frozen and the CPU en-
ters STOP mode.
When the MCU exits STOP mode (i.e. when an in-
terrupt is generated), the Watchdog resumes its
activity.
Table 7. Recommended Option Choices
Functions Required
Stop Mode & Watchdog
Stop Mode
Watchdog
Recommended Options
“EXTERNAL STOP MODE” & “HARDWARE WATCHDOG”
“SOFTWARE WATCHDOG”
“HARDWARE WATCHDOG”
23
相关PDF资料
PDF描述
ST62E28CF1 8-BIT MICROCONTROLLER ( MCU ) WITH OTP. ROM. FASTR A/D CONVERTER. 8-BIT AUTO-RELOAD TIMER. UART. OSG. SAFE RESET AND 28 PINS
ST62P28CB1 8-BIT MICROCONTROLLER ( MCU ) WITH OTP. ROM. FASTR A/D CONVERTER. 8-BIT AUTO-RELOAD TIMER. UART. OSG. SAFE RESET AND 28 PINS
ST62P28CB3 8-BIT MICROCONTROLLER ( MCU ) WITH OTP. ROM. FASTR A/D CONVERTER. 8-BIT AUTO-RELOAD TIMER. UART. OSG. SAFE RESET AND 28 PINS
ST62P28CB6 8-BIT MICROCONTROLLER ( MCU ) WITH OTP. ROM. FASTR A/D CONVERTER. 8-BIT AUTO-RELOAD TIMER. UART. OSG. SAFE RESET AND 28 PINS
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相关代理商/技术参数
参数描述
ST6228CB1 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:8-BIT MCUs WITH A/D CONVERTER, AUTO-RELOAD TIMER, UART, OSG, SAFE RESET AND 28-PIN PACKAGE
ST6228CB1/XXX 制造商:未知厂家 制造商全称:未知厂家 功能描述:8-Bit Microcontroller
ST6228CB3 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:8-BIT MCUs WITH A/D CONVERTER, AUTO-RELOAD TIMER, UART, OSG, SAFE RESET AND 28-PIN PACKAGE
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ST6228CB6 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:8-BIT MCUs WITH A/D CONVERTER, AUTO-RELOAD TIMER, UART, OSG, SAFE RESET AND 28-PIN PACKAGE