DS1343E-33+ Maxim Integrated Products, DS1343E-33+ Datasheet - Page 18

• Manufacturer Part Number: DS1343E-33+
• Description: Real Time Clock SONET/SDH sync IC CSBGA LEADED
• Manufacturer: Maxim Integrated Products

Burst mode is similar to a single-byte read or write,
except that CE is kept high and additional SCLK cycles
are sent until the end of the burst. The clock registers
and the user RAM can be read or written in burst mode.
The address pointer wraps around to 00h after reaching
1Fh (RTC), and the address pointer wraps around to 20h
after reaching 7Fh (RAM). See Figure 6.
The 3-wire interface mode operates similarly to the SPI
mode. However, in 3-wire mode there is one I/O instead
of separate data-in and data-out signals. The 3-wire
interface consists of the I/O (SDI and SDO pins con-
nected together), CE, and SCLK pins. In 3-wire mode,
each byte is shifted in LSB first, unlike SPI mode, where
each byte is shifted in MSB first.
As is the case with the SPI mode, an address byte is
written to the device followed by a single data byte or
multiple data bytes. Figure 7 illustrates a write cycle, and
Figure 8 illustrates a read cycle. In 3-wire mode, data is
Low-Current SPI/3-Wire RTCs
Figure 7. 3-Wire Single-Byte Write
Figure 8. 3-Wire Single-Byte Read
18
CE
SCLK
I/O*
*I/O IS SDI AND SDO CONNECTED TOGETHER.
SERMODE = GND.
CE
SCLK
I/O*
*I/O IS SDI AND SDO CONNECTED TOGETHER.
SERMODE = GND
HIGH-Z
HIGH-Z
Reading and Writing in Burst Mode
A0
A0
A1
A1
3-Wire Interface
A2
A2
A3
A3
A4
A4
A5
A5
A6
A6
R/W
1
R/W
0
input on the rising edge of SCLK and output on the falling
edge of SCLK.
To achieve the best results when using the devices,
decouple the V
0.1µF capacitor. Use a high-quality, ceramic, surface-
mount capacitor if possible. Surface-mount components
minimize lead inductance, which improves performance,
and ceramic capacitors tend to have adequate high-
frequency response for decoupling applications.
The INT0 and INT1 outputs are open drain and therefore
require external pullup resistors to realize a logic-high
output level.
The devices contain Maxim’s redundant battery-charge
protection circuit to prevent any charging of an external
battery.
D0
D0
D1
D1
D2
D2
CC
Applications Information
D3
D3
power supply with a 0.01µF and/or
Battery Charge Protection
Using Open-Drain Outputs
D4
Power-Supply Decoupling
D4
D5
D5
D6
D6
D7
D7