參數(shù)資料
型號(hào): SAB-C505A-4EM
廠商: SIEMENS A G
元件分類: 微控制器/微處理器
英文描述: 8-Bit CMOS Microcontroller
中文描述: 8-BIT, OTPROM, 20 MHz, MICROCONTROLLER, PQFP44
封裝: PLASTIC, MQFP-44
文件頁數(shù): 48/85頁
文件大?。?/td> 335K
代理商: SAB-C505A-4EM
Semiconductor Group
48
1997-12-01
C505 / C505C
C505A / C505CA
Fail Save Mechanisms
The C505 offers enhanced fail safe mechanisms, which allow an automatic recovery from software
upset or hardware failure :
– a programmable watchdog timer (WDT), with variable time-out period from 192
μ
s up to
approx. 412.5 ms at 16 MHz.
– an oscillator watchdog (OWD) which monitors the on-chip oscillator and forces the
microcontroller into reset state in case the on-chip oscillator fails; it also provides the clock for
a fast internal reset after power-on.
The watchdog timer in the C505 is a 15-bit timer, which is incremented by a count rate of
f
OSC
/12
upto
f
OSC
/192. The system clock of the C505 is divided by two prescalers, a divide-by-two and a
divide-by-16 prescaler. For programming of the watchdog timer overflow rate, the upper 7 bits of the
watchdog timer can be written.
Figure 24
shows the block diagram of the watchdog timer unit.
Figure 24
Block Diagram of the Programmable Watchdog Timer
The watchdog timer can be started by software (bit SWDT in SFR IEN1) but it cannot be stopped
during active mode of the device. If the software fails to refresh the running watchdog timer an
internal reset will be initiated on watchdog timer overflow. For refreshing of the watchdog timer the
content of the SFR WDTREL is transfered to the upper 7-bit of the watchdog timer. The refresh
sequence consists of two consequtive instructions which set the bits WDT and SWDT each. The
reset cause (external reset or reset caused by the watchdog) can be examined by software (flag
WDTS). It must be noted, however, that the watchdog timer is halted during the idle mode and
power down mode of the processor.
MCB03306
IP0 (A9 )
OSC
f
WDTS
2
16
14
0
7
8
WDTL
WDTH
/ 6
External HW Reset
Control Logic
IEN0 (A8 )
IEN1 (B8 )
6
7
0
WDT Reset - Request
WDTPSEL
WDTREL (86 )
WDT
SWDT
OWDS
相關(guān)PDF資料
PDF描述
SAF-C505A-4EM 8-Bit CMOS Microcontroller
SAF-C505-2RM 8-Bit CMOS Microcontroller
SAB-C505-2RM 8-Bit CMOS Microcontroller
SAB-C513AO 8-bit CMOS Microcontroller
SAF-C513AO 8-bit CMOS Microcontroller
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
SAB-C505A-4EM-BA 制造商:Rochester Electronics LLC 功能描述:- Bulk
SAB-C505C-2RM 制造商:INFINEON 制造商全稱:Infineon Technologies AG 功能描述:8-Bit CMOS Microcontroller
SAB-C505CA-4EM 制造商:Infineon Technologies 功能描述:Bulk
SAB-C505CA-4EM CA 功能描述:8位微控制器 -MCU 8 BIT OTP RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
SAB-C505CA-4EM CATR 制造商:Infineon Technologies AG 功能描述: