MAX6953 Maxim Integrated Products, MAX6953 Datasheet - Page 6

• Manufacturer Part Number: MAX6953
• Description: 2-Wire Interfaced/ 2.7V to 5.5V/ 4-Digit 5 x 7 Matrix LED Display Driver
• Manufacturer: Maxim Integrated Products

2-Wire Interfaced, 2.7V to 5.5V, 4-Digit 5
Matrix LED Display Driver
Figure 1. MAX6953 Functional Diagram
The MAX6953 is a serially interfaced display driver that
can drive four digits of 5
plays. The MAX6953 can drive either four monocolor
digits (Table 1) or two bicolor digits (Table 2). The
MAX6953 includes a 128-character font map compris-
ing 104 predefined characters and 24 user-definable
characters. The predefined characters follow the Arial
font, with the addition of the following common symbols:
£, <, ¥, °, µ, ±, ↑, and ↓. The 24 user-definable charac-
Table 1. Connection Scheme for Four Monocolor Digits
Table 2. Connection Scheme for Two Bicolor Digits
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DIGIT
DIGIT
1
2
1
2
BLINK
_______________________________________________________________________________________
ISET
OSC
SCL
SDA
AD0
AD1
Digit 0 rows (cathodes) R1 to R7
Digit 1 rows (cathodes) R1 to R7
Digit 0 rows (cathodes)
COUNTER
NETWORK
DIVIDER/
CURRENT
SOURCE
SELECT
SPEED
BLINK
R1 to R14
O0–O6
O0–O6
RAM
—
—
Detailed Description
CHARACTER
GENERATOR
SERIAL INTERFACE
✕
RAM
MULTIPLEXER
BRIGHTNESS
CONTROL
7 cathode-row dot-matrix dis-
PWM
ROW
CONFIGURATION
REGISTERS
CHARACTER
GENERATOR
ROM
DRIVERS
Digit 2 rows (cathodes) R1 to R7
Digit 3 rows (cathodes) R1 to R7
LED
Digit 1 rows (cathodes)
O0 TO O23
R1 to R14
O7–O13
O7–O13
—
—
ters are uploaded by the user into on-chip RAM through
the serial interface and are lost when the device is pow-
ered down. Figure 1 is the MAX6953 functional diagram.
The MAX6953 operates as a slave that sends and
receives data through an I
face. The interface uses a serial data line (SDA) and a
serial clock line (SCL) to achieve bidirectional commu-
nication between master(s) and slave(s). A master (typ-
ically a microcontroller) initiates all data transfers to and
from the MAX6953, and generates the SCL clock that
synchronizes the data transfer (Figure 2).
The MAX6953 SDA line operates as both an input and
an open-drain output. A pullup resistor, typically 4.7kΩ,
is required on the SDA. The MAX6953 SCL line oper-
ates only as an input. A pullup resistor, typically 4.7kΩ,
is required on SCL if there are multiple masters on the
2-wire interface, or if the master in a single-master sys-
tem has an open-drain SCL output.
Each transmission consists of a START condition
(Figure 3) sent by a master, followed by the MAX6953
7-bit slave address plus R/W bit (Figure 6), a register
address byte, 1 or more data bytes, and finally a STOP
condition (Figure 3).
Both SCL and SDA remain high when the interface is
not busy. A master signals the beginning of a transmis-
sion with a START (S) condition by transitioning SDA
from high to low while SCL is high. When the master
has finished communicating with the slave, it issues a
STOP (P) condition by transitioning the SDA from low to
high while SCL is high. The bus is then free for another
transmission (Figure 3).
- the 5 green columns -
Digit 0 columns (anodes)
Digit 2 columns (anodes)
- the 5 green anodes -
Digit 0 columns (anodes) C1 to C10
Digit 1 columns (anodes) C1 to C10
O14–O18
C1 to C5
C1 to C5
2
Start and Stop Conditions
O14–023
C-compatible 2-wire inter-
Serial Interface
- the 5 red anodes -
- the 5 red anodes -
Serial Addressing
(anodes) C6 to C10
(anodes) C6 to C10
✕
Digit 1 columns
Digit 3 columns
O19-–O23
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