參數(shù)資料
型號: DS2404
英文描述: EconoRAM Time Chip
中文描述: 經(jīng)濟(jì)型RAM時(shí)鐘芯片
文件頁數(shù): 6/28頁
文件大小: 663K
代理商: DS2404
DS2404
6 of 28
020998
MEMORY
The memory map in Figure 4 shows a page (32 bytes) called the scratchpad and 17 pages called memory.
Pages 0 through 15 each contain 32 bytes which make up the 4096-bit SRAM. Page 16 has only 30 bytes
which contain the timekeeping registers.
The scratchpad is an additional page of memory that acts as a buffer when writing to memory. Data is
first written to the scratchpad where it can be read back. After the data has been verified, a copy
scratchpad command will transfer the data to memory. This process ensures data integrity when
modifying the memory.
TIMEKEEPING
A 32.768 kHz crystal oscillator is used as the time base for the timekeeping functions. The oscillator can
be turned on or off by an enable bit in the control register. The oscillator must be on for the real time
clock, interval timer, cycle counter and 1 Hz output to function.
The timekeeping functions are double buffered. This feature allows the master to read time or count
without the data changing while it is being read. To accomplish this, a snapshot of the counter data is
transferred to holding registers which the user accesses. This occurs after the eighth bit of the Read
Memory Function command.
Real-Time Clock
The real-time clock is a 5-byte binary counter. It is incremented 256 times per second. The least
significant byte is a count of fractional seconds. The upper four bytes are a count of seconds. The real-
time clock can accumulate 136 years of seconds before rolling over. Time/date is represented by the
number of seconds since a reference point which is determined by the user. For example, 12:00A.M.,
January 1, 1970 could be a reference point.
Interval Timer
The interval timer is a 5-byte binary counter. When enabled, it is incremented 256 times per second. The
least significant byte is a count of fractional seconds. The interval timer can accumulate 136 years of
seconds before rolling over. The interval timer has two modes of operation which are selected by the
MAN
AUTO/
bit in the control register. In the auto mode, the interval timer will begin counting after the
I/O line has been high for a period of time determined by the DSEL bit in the control register. Similarly,
the interval timer will stop counting after the I/O line has been low for a period of time determined by the
DSEL bit. In the manual mode, time accumulation is controlled by the
register.
START
STOP/
bit in the control
NOTE: For auto mode operation, the high level on the I/O pin must be greater than or equal to 70% of
V
CC
or V
BATO
.
Cycle Counter
The cycle counter is a 4-byte binary counter. It increments after the falling edge of the I/O line if the
appropriate I/O line timing has been met. This timing is selected by the DSEL bit in the control register.
(See “Status/ Control” section).
NOTE: For cycle counter operation, the high level on the I/O pin must be greater than or equal to 70% of
V
CC
or V
BATO
.
相關(guān)PDF資料
PDF描述
DS2404-001 EconoRAM Time Chip
DS2404B EconoRAM Time Chip
DS2404S EconoRAM Time Chip
DS2405 Addressable Switch
DS2405P Addressable Switch
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS2404-001 制造商:Maxim Integrated Products 功能描述:ECONORAM/TIME, DIP16 (GENERIC) - Rail/Tube
DS2404-001+ 制造商:Maxim Integrated Products 功能描述:REAL TIME CLOCK SERL 512BYTE 16PDIP - Rail/Tube
DS2404B 功能描述:實(shí)時(shí)時(shí)鐘 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube
DS2404B/T&R 制造商:Maxim Integrated Products 功能描述:ECONORAM/TIME, SSOP16-TRL (GENERIC) - Tape and Reel
DS2404B+ 制造商:Maxim Integrated Products 功能描述:REAL TIME CLOCK SERL 512BYTE 16SSOP - Rail/Tube