MAX6960 MAXIM [Maxim Integrated Products], MAX6960 Datasheet - Page 26

• Manufacturer Part Number: MAX6960
• Description: 4-Wire Serially Interfaced 8 x 8 Matrix Graphic LED Drivers
• Manufacturer: MAXIM [Maxim Integrated Products]

Writing the global clear planes counter (Table 31) allows
any or all display memory planes to be cleared with one
command. The selected plane(s) are cleared on the ris-
ing edge of CS at the end of the 16-bit transmission.
The MAX6960 detects open-circuit and short-circuit
LEDs. It can only detect an LED fault when attempting
to light that LED, so a good strategy to check a panel is
to program the panel with all LEDs on power-up to
check the displays.
The fault and device ID register (Table 32) uses 3 bits
to flag and distinguish open-circuit (open flag), short-
circuit (short flag), and overtemperature (OT flag)
faults, and a fourth flag (fault flag), which is an OR of
the open flag, short flag, and OT flag.
The fault and device ID register is cleared on power-
up, and can also be cleared by writing to it. The fault
flags are NOT cleared by a read. When writing the fault
register, the data written is ignored; all fault flags are
cleared, including the OT flag. It is possible to clear all
MAX6960s on a bus by performing a global write to the
fault and device ID register.
The MAX6960 contains an overtemperature (OT) detec-
tion circuit, which trips at a die temperature of typically
+150°C. The OT event is latched, and is readable in the
fault and device ID register (Table 32). When the OT
trips, the MAX6960 shutdown bit in the configuration
4-Wire Serially Interfaced
8 x 8 Matrix Graphic LED Drivers
Table 30. Global Plane Counter Register Format (continued)
26
Auto fast plane counter—2 frames per
second
—
Auto fast plane counter— 62 frames
per second
Auto fast plane counter— 63 frames
per second
______________________________________________________________________________________
PLANE COUNTER
Overtemperature Fault Detection
REGISTER
Global Clear Planes Command
LED Fault Detection
Fault Detection
PLANES/INTENSITY BIT
0 FOR 1 BIT/PIXEL;
1 FOR 1 BIT/PIXEL;
(SEE TABLE 22):
4 PLANES
4 PLANES
register (Table 31) is cleared, and the driver goes into
shutdown. Data is not lost; the effect is the same as the
user setting the shutdown bit. The user can attempt to
set the shutdown bit at any time. However, if the driver
is still over temperature, then the attempt to set the
shutdown bit is ignored. The OT fault flag is NOT auto-
matically cleared when the device cools, or when the
device is taken out of shutdown.
The fault and device ID register is cleared on power-
up, and can also be cleared by writing to it. The fault
flags are NOT cleared by a read. When writing the fault
register, the data written is ignored; all fault flags are
cleared, including the LED flags. It is possible to clear
all MAX6960s on a bus by performing a global write to
the fault and device ID register.
The MAX6960 can be configured for pretrimmed 20mA
or 40mA LED current, or a 20mA to 40mA adjustable
current, on a digit-by-digit basis by the RISET0 and
RISET1 pin connections (Figures 13 and 14). The digit
intensity registers can be used to digitally adjust the
segment current, again on a digit-by-digit basis, by
controlling the PWM. Some applications best use one
or the other technique; some applications may require
the flexibility of both.
The MAX6960 operates from a single 2.7V to 3.6V
power supply. Accuracy of the LED drive current of
20mA is guaranteed over this supply range. Accuracy
ADDRESS
CODE
(HEX)
0x0B
0x0B
0x0B
0x0B
slow
Fast
D7
1
1
1
1
Applications Information
manual
Auto
D6
1
1
1
1
Setting LED Drive Current
REGISTER DATA
D5
—
0
1
1
D4
—
0
1
1
Counter setting
Power Supplies
D3
—
0
1
1
D2
—
0
1
1
D1
—
1
1
1
D0
—
0
0
1