MAX6946EVKIT Maxim Integrated, MAX6946EVKIT Datasheet - Page 6

• Manufacturer Part Number: MAX6946EVKIT
• Description: LED Lighting Development Tools 10-Port Constant-Current LED Driver and I/O Expander with PWM Intensity Control
• Manufacturer: Maxim Integrated
• Series: MAX6946, MAX6947r

Specifications of MAX6946EVKIT

• Product: Demonstration Boards

20mA and the Hold-Off Delay, Ramp-Down Time, and
Ramp-Up Time from 0 to 4s. The other configuration
register bits can be programmed by configuring the
OSC/AD0, RSTPOR, PWM Staggered, Reset Run,
and Run Enable GUI controls. The Read P7-P0 and
Read P9-P8 buttons can be used to read the logical
state of the MAX6946 P7–P0 and P9 to P8 pins, repec-
tively. Refer to the MAX6946/MAX6947 IC data sheet
for a detailed description of each of these functions.
Note: During Read P7-P0 and Read P9-P8 operations,
the software automatically changes the r/w bit in the
address from 0 to 1 for proper I
The GUI tabs allow the user to configure the 10 I/O
ports individually or in groups. Once a port(s) tab has
been selected, the P_ Configuration group box allows
the user to configure the port as a Low-Logic Output,
High-Logic Output/ Logic Input, Static Constant-
Current Sink, constant-current PWM output (PWM
Duty Cycle slide bar), or disable the LED(s) (LED Off).
Individual port Sink Current can be configured to half
or full of the global current setting (Global Current
Sink). Configuring the I/O ports to Low-Logic Output
turns on the LEDs without regulating the LED current at
the respective port. Use the mouse or keyboard
left/right arrows to move the PWM Duty Cycle slide bar
from left to right to dim or brighten the LED(s). Refer to
the MAX6946/MAX6947 IC data sheet for a detailed
description of each of these registers. For true logic
input or output configuration of each port, remove the
shunts on header J2, install pullup resistors on PC pads
R2–R11, and use the software to configure the ports for
logic outputs or inputs. Refer to the I/O Ports section in
the MAX6946/MAX6947 IC data sheet for further
details.
There are two methods for communicating with the
MAX6946; through the normal user-interface panel
(Figure 1) or by using low-level I
able through the 2-wire interface diagnostics (Figure
MAX6946 Evaluation Kit/Evaluation System
6
_______________________________________________________________________________________
Configuring the I/O Ports
Simple I
2
C read operation.
2
C commands avail-
2
C Commands
2) item from the main program’s Options menu. A win-
dow is displayed that allows I
read byte and write byte. To stop normal user-interface
execution so that it does not override the manually set
values, turn off the update timer by unchecking the
Automatic Diagnostics checkbox in the MAX6946
main program.
The I
decimal, or hexadecimal. Hexadecimal numbers must
be prefixed by $ or 0x. Binary numbers must be exactly
eight digits of 0s and 1s. See Figure 2 for an example
using the 2-wire interface diagnostics tool.
Note: When using low-level I
interface is no longer synchronized and will not reflect
the IC register settings.
Problem: software reports it cannot find the board.
• Is the CMAXQUSB interface board power LED
• Is the USB communications cable connected?
• Has windows plug-and-play detected the board?
Problem: Unable to find DUT (device-under-test).
• Is power connected to the MAX6946 EV kit?
• Are the SCL and SDA signals pulled up to VDD
• If using jumper wires to connect to the I
(LED1) lit?
Bring up Control Panel | System | Device Manager,
and look at what device nodes are indicated for
USB. If there is an “unknown device” node attached
to the USB, delete it—this forces plug-and-play to try
again.
through appropriate resistors (2.4kΩ typ)? The
CMAXQUSB interface board dip-switch SW1
enables the on-board resistors. There must be
pullup resistors somewhere on the I
could the SCL and SDA signals be swapped? Could
the GND ground return be missing?
2
C dialog boxes accept numeric data in binary,
General Troubleshooting
2
2
C commands, the GUI
C operations, such as
2
C bus.
2
C bus,