NXP Semiconductors PCA9955A User manual

UM10729
PCA9955A/B demonstration board OM13483
Rev. 2 — 1 August 2017 User manual
Document information
Info Content
Keywords Fm+ I2C-bus, PCA9955A/B, RGB and White LEDs, 16-channel x 8-bit
PWMs
Abstract The OM13483 is an add-on to 9-pin connector of the NXP I2C demo board
2005-1 or Fm+ I2C-bus development board. This daughter board makes it
easy to test and design with the PCA9955A/B, a 16-channel Fast-mode
Plus (Fm+) 57 mA constant current and outputs allow up to 20 V for LED
supply. This demo board, along with the Win-I2CUSB Lite GUI
(PC based), provides an easy to use evaluation platform.

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Contact information
For more information, please visit: http://www.nxp.com
For sales office addresses, please send an email to: [email protected]
NXP Semiconductors UM10729
PCA9955A/B demonstration board OM13483
Revision history
Rev Date Description
2.0 20170801 Added PCA9955B; updated schematics
1.0 20140723 User manual; initial release.

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PCA9955A/B demonstration board OM13483
1. Introduction
The PCA9955A/B evaluation board features LEDs for color mixing, blinking and dimming
demonstrations. A graphical interface allows the user to explore the different functions of
the driver easily. The board can be connected in series with other I2C demo-boards to
create an evaluation system.
The IC communicates to the host via the industry standard I2C-bus/SMBus port. The
evaluation software runs under Microsoft Windows PC platform.
2. Features
•A complete evaluation platform for the PCA9955A/B 16-channel Fm+ I2C-bus
constant current LED driver
•Easy to use GUI-based software demonstrates the capabilities of the PCA9955A/B
•On-board four white and four RGB LEDs for visual experience
•Convenient test points for easy scope measurements and signal access
•USB interface to the host PC
•No external power supply required
3. Getting started
3.1 Assumptions
Familiarity with the I2C-bus is helpful, but not required.
3.2 Static handling requirements
3.3 Minimum system requirements
•PC Pentium 60 processor (or equivalent), 8 MB RAM, 10 MB of hard drive space
•One USB port (either 2.0 or 1.1 compatible)
•Windows 98SE, ME, 2000, XP, or Vista
•I2C demonstration board 2005-1 (OM6275) or Win-I2CUSB board (from
www.demoboard.com)
3.4 Power requirements
The NXP demonstration board I2C 2005-1 and OM13483 hardware obtain power from the
PC USB port. Care should be taken not to exceed the USB port current capabilities.
CAUTION
This device is sensitive to ElectroStatic Discharge (ESD). Therefore care should be taken
during transport and handling. You must use a ground strap or touch the PC case or other
grounded source before unpacking or handling the hardware.

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PCA9955A/B demonstration board OM13483
4. Installation
4.1 I2C demo board 2005-1 and Win-I2CUSB Lite software
The OM13483 is a daughter card to the OM6275 I2C demo board 2005-1. You may
download the Win-I2CUSB Lite Software, the OM6275 user manual UM10206, and find
ordering information at the NXP web site www.nxp.com/demoboard/OM6275.html.
The OM13483 is a daughter card to the OM13260 Fm+ I2C-bus development board,
which is part of the Fm+ development board kit (OM13320). You may download the
software, user manual, and find ordering information at the NXP web site:
www.nxp.com/demoboard/OM13320.html#documentation.
The Win-I2CUSB Lite software from The Boardshop runs on Windows 98SE, ME, 2000,
and XP and is compatible with any PC hardware having a minimum of a Pentium
processor and a USB port. The software allows the user to select one of the I2C-bus
devices on the board from a menu. It also provides a Universal mode (I2C Expert mode) to
allow users to create their own I2C-bus commands with the same I2C-bus devices.
4.2 OM13483 connection to I2C demo board 2005-1
The I2C demo board 2005-1 should be disconnected from your PC before mounting the
OM13483 board on to it. The OM13483 board has a 9-pin female connector (CON2) that
connects to the JP1 male connector on the I2C demo board 2005-1 as shown in Figure 1.
With both boards facing you, and with USB connector on the right-hand side as shown in
Figure 1, connect the OM13483 board to the I2C demo board 2005-1 before connecting
the USB cable. Once the board is connected, connect the USB cable and start the
Win-I2CUSB Lite software. You are now ready to evaluate the PCA9955A/B.

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PCA9955A/B demonstration board OM13483
Fig 1. PCA9955A/B demo board (OM13483) mounting to the I2C demo board 2005-1
(OM6275)

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PCA9955A/B demonstration board OM13483
4.3 OM13483 connection to Fm+ I2C bus development board
The OM13260 Fm+ I2C bus development board should be disconnected from your PC
before mounting the OM13483 board onto it. The OM13483 board has a 9-pin female
connector (CON2) that connects to the CN2 male connector on the bridge board
(OM13399) as shown in Figure 2.
Fig 2. PCA9955A/B demo board (OM13483) mounting to the Fm+ development board (OM13260)
aaa-014227
PCA9955A
demo board
(OM13483)
14-pin connector
Select Bus 1
to drive PCA9955A
Fm+ development board
(OM13260)
Bridge board
(OM13399)
9-pin connector
To PC
USB port

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PCA9955A/B demonstration board OM13483
4.4 OM13483 connection to Win-I2CUSB hardware adapter board
The Win-I2CUSB board should be disconnected from your PC before connecting the
OM13483 board on to it. The OM13483 board has a 14-pin male connector (CON4) that
connects to the 14-pin male connector (J1) on the Win-I2CUSB board as shown in
Figure 3.
Connect the OM13483 board to the Win-I2CUSB board before connecting the USB cable.
Once the board is connected, connect the USB cable and start the Win-I2CUSB Lite
software. You are now ready to evaluate the PCA9955A/B.
Fig 3. PCA9955A/B demo board (OM13483) connecting to the Win-I2CUSB board

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PCA9955A/B demonstration board OM13483
5. Hardware description
Figure 4 shows the following items on the hardware:
•CON1 (9-pin male connector) is used to daisy-chain to next I2C-bus slave device or
demo board.
•CON2 (9-pin female connector) is connected to JP1 on I2C demo board 2005-1 as
master device to drive this demo board.
•CON3 (5-pin male connector) is connected to the PCU9669 or PCA9665 mini board
as I2C-bus master device to drive this demo board.
•CON4 (14-pin male connector) is connected to J1 on Win-I2CUSB hardware board as
I2C-bus master device to drive this demo board.
•J1 selects VDD power for PCA9955A/B, connected 1-2 for VDD = 5 V and connected
2-3 for VDD =3.3V.
•J7, J9 and J10 to select one of the five (GND, Pull-down, Floating, Pull-up and VDD)
input levels to address inputs AD[0:2] for a maximum of 125 possible programmable
I2C-bus slave address.
•LED[0:15] 16-channel output to drive four White LEDs (WHT_LED[1:4]) and four RGB
LEDs (RGB_LED[1:4]).
•TP2 and TP3 are GND pins for probing use.
•TP1 can be connected as external reset signal to RESET pin when J6 is open.
•TP4 can be connected as external output enable signal to OE pin for blinking/dimming
control when J11 is open.
•All jumpers default setting and function as shown in Table 1.
Fig 4. PCA9955A/B demo board (OM13483)

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PCA9955A/B demonstration board OM13483
Table 1. Jumper settings for test and evaluation
Jumper Default setting Comment
J1
(3-pin) 1-2 (VDD = +5 V) This jumper is used to select VDD for PCA9955A/B.
1-2: select +5 V
2-3: select +3.3 V
J2
(3 2-pin) 1-2 (REXT = 1 k,
57 mA at max.)
This 3 2 jumper is used to select REXT (pin 1) value for PCA9955A/B.
1-2: select REXT = 1 kand maximum output current is 57.3 mA
3-4: select REXT = 1.5 kand maximum output current is 38.25 mA
5-6: select REXT = 2 kand maximum output current is 28.6 mA
J3
(2-pin) Short Short: external 1.1 kpull-up resistor for SDA on PCA9955A/B.
Open: no external pull-up resistor for SDA on PCA9955A/B.
Remark: No external pull-up resistor required for PCU9955A.
J4
(2-pin) Short Short: external 1.1 kpull-up resistor for SCL on PCA9955A/B.
Open: no external pull-up resistor for SCL on PCA9955A/B.
Remark: No external pull-up resistor required for PCU9955A.
J5
(2-pin) Short Short: connect VDD (pin 28) to PCA9955A/B.
Open: connect current meter to measure the IDD on PCA9955A/B.
J6
(2-pin) Open Short: force RESET (pin 25) to GND.
Open: 10 kpull-up RESET (pin 25) to VDD.
J7
(4 2-pin) 7-8[1] This 4 2 jumper is used to select quinary input value for AD0 (pin 2).
Open: floating
1-2: select VDD
3-4: select pull-up with 31.6 k
5-6: select pull-down with 34.8 k
7-8: select GND
J8
(3-pin) 1-2 This jumper is used to select bus mode.
1-2: select normal I2C or SPI addressable bus mode
2-3: select SPI daisy-chain bus mode
J9
(5 2-pin) 7-8[1] This 5 2 jumper is used to select quinary input value for AD1 (pin 3).
Open: floating
1-2: select VDD
3-4: select pull-up with 31.6 k
5-6: select pull-down with 34.8 k
7-8: select GND
9-10: SDO (Serial Data Out) for SPI addressable mode or last slave device in SPI
daisy-chain
J10
(5 2-pin) 7-8[1] This 5 2 jumper is used to select quinary input value for AD2 (pin 4).
Open: floating
1-2: select VDD
3-4: select pull-up with 31.6 k
5-6: select pull-down with 34.8 k
7-8: select GND
9-10: CSN (Chip Select) for SPI bus mode
J11
(2-pin) Short Short: force OE (pin 5) to GND, to enable LEDs output.
Open: 10 kpull-up OE (pin 5) to VDD when applying external clock for blinking/dimming on
TP4 (test point).

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PCA9955A/B demonstration board OM13483
[1] Default PCA9955A/B slave address is 0x02h (AD[2:0] = GND).
J12, J16,
J19, J22
(2-pin)
Short These jumpers are used to open the WHT_LED1 or RGB_LED1 J12 to control White LED,
J16 to control Red LED, J19 to control Green LED, J22 to control Blue LED.
Open: connected the current meter to measure one of the LEDs output current or open one
of the LEDs outputs for detecting an LED open condition in one of EFLAGn registers.
Short: normal operation for WHT_LED1 and RGB_LED1.
J13
(3-pin) 1-2 (VLED = +3.3 V) This jumper is used to select LED supply voltage.
1-2: select +3.3 V for all LEDs supply voltage.
2-3: select +5 V for all LEDs supply voltage.
Open (no jumper): select external voltage from J20 (+20 V) and J24 (GND)
J14, J18
(2-pin) Open These jumpers are used to merge the LED[0:2] outputs together for driving higher LED current.
Open: normal operation for the LED[0:2].
Short: When short J14/J18 and open J16/J19 to combine LED[0:2] outputs to drive LED0.
When short J14 only and open J16 to combine LED[0:1] outputs to drive LED0.
J15, J17,
J21, J23
(2-pin)
Open These jumpers are used to short the WHT_LED1 or RGB_LED1 J15 to control White LED,
J17 to control Red LED, J23 to control Green LED, J21 to control Blue LED.
Open: normal operation for WHT_LED1 and RGB_LED1.
Short: to short one of the LEDs output for detecting an LED short condition in one of
EFLAGn registers.
J20
(2-pin) +20 V input External +20 V input for LEDs supply voltage. The J13 is open to supply this +20 V voltage to all LEDs.
J24
(2-pin) GND External GND input for LEDs supply voltage.
J25, J27,
J29, J31
(2-pin)
Short These jumpers are used to open the WHT_LED4 or RGB_LED4.
J25 to control White LED, J27 to control Red LED, J29 to control Green LED, J31 to control
Blue LED.
Open: connect current meter to measure one of the LEDs output current or open one of the
LEDs outputs for detecting an LED open condition in one of EFLAGn registers.
Short: normal operation for WHT_LED4 and RGB_LED4.
J26, J28,
J30, J32
(2-pin)
Open These jumpers are used to short the WHT_LED4 or RGB_LED4.
J26 to control White LED, J28 to control Red LED, J32 to control Green LED, J30 to control
Blue LED.
Open: normal operation for WHT_LED4 and RGB_LED4.
Short: to one of the LEDs for detecting an LED short condition in one of EFLAGn registers.
CON1 9-pin male
connector This 9-pin connector is used to daisy-chain to next I2C-bus slave device or demo board.
CON2 9-pin female
connector This 9-pin connector is used to connect to Fm+ I2C development board or I2C 2005-1
evaluation board as master device to drive this demo board.
CON3 5-pin male
connector This 5-pin connector is used to connect to the PCU9669 or PCA9665 mini board as I2C-bus
master device to drive this demo board.
CON4 14-pin header This 14-pin header is used to connect to Win-I2CUSB hardware board as I2C-bus master
device to drive this demo board.
TP1 Test Point 1 This TP1 is used to drive RESET input pin 25 from external when J6 is open.
TP2, TP3 Test Point 2/3 These two test points are GND for probe ground connection.
TP4 Test Point 4 This TP4 is used to drive OE input pin 5 from external when J11 is open.
Table 1. Jumper settings for test and evaluation …continued
Jumper Default setting Comment

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PCA9955A/B demonstration board OM13483
6. Schematic
Fig 5. PCA9955A/B demo board schematic (part A)
aaa-013943
PCA9955A/PCA9955B (OM13483)
16-ch 57mA/20V CC LED driver Test/Demo Board
(Io_LED_MAX=28.6mA)
(Io_LED_MAX=38.25mA)
(Io_LED_MAX=57.3mA)
Quinary input pad connection to AD[2:0]
Open -> floating
1-2 -> VDD
3-4 -> Pull-up
5-6 -> Pull-down
7-8 -> GND
Ext /OE input
1-2: LED output control
Open -> Output disabled
Short -> Output enabled
Ext /RST input
9-pin female connector
to/from I2C 2005-1 board
9-pin male connector to/from
2nd PCA9955A/B demo board
(470ohm@100MHz)
14-pin header connector to/from
Win-I2CUSB I2C master to drive
PCA9955A/B demo board
GND
GND
LED max. output current setting:
1-2 -> Rext=1K, 57.3mA = 225uA x 255
3-4 -> Rext=1.5K, 38.25mA = 150 uA x 255
5-6 -> Rext=2K, 28.6mA = 112.5 x 255
AD0
AD1
AD2
closed to Vdd pin
5-pin male connector to/from
bus controller PCU9669 mini
board to drive PCA9955A/B
1-2 -> force reset
Open -> noraml
Note:
OM13399 can use to connect this 9-pin female connector
and convert to 14-pin for new I2C development board
Thermal pad 5.5 x 2.2 mm
add thermal vias 5 x 2
0.28 mm diameter with 1 mm pitch
with the barrel plated to about 1.0 ounce copper
(Green LED for
Vdd indicator)
open to measure
the U1 current
open (no PU)
for PCU9955A
1-2: normal I2C or SPI addressable
2-3: SPI daisy-chain
(SPI_SCLK)
(SPI_SCLK)
(SPI_SDI)
(Pins [5:9] to/from the
SPI master device)
(Pins [5:9] to/from the
2nd SPI slave PCA9955A
demo board)
(short 9-10 for SPI mode)
(short 9-10 for the last slave
device in SPI daisy-chain)
Pin #
2
3
4
26
27
PCA9955B
(I2C-bus)
AD0
AD1
AD2
SCL
SDA
PCA9745B
(SPI Daisy-Chain)
GND
SDO
/CS
SCLK
SDI
Jumper #
J7
J9
J10
NA
J8
(short 7-8 for PCA9745B)
SPI Daisy-Chain
SCL
SDA
VDD_IN
GND
+3.3V +5V
SDA-Filter
SCL-Filter
VDD_IN
LED0
LED1
LED2
LED3
LED9
LED10
LED11
LED12
LED13
LED14
LED15
AD0
VDD_IN /OE
SCL-Filter
/RESET
+5V
+3.3V
SCL
GND
SPI_SDI
SPI_CSN
+5V
+3.3V
SCL-Filter
SDA-Filter
SPI_CSN
VDD_IN
VDD_IN
SCL
SDA
+5V+3.3V GND
GND
LED[0:15]
SCL-Filter
SDA-Filter
+24V
+5V
SDA-Filter
SCL-Filter
GND
LED8LED7
LED6
LED5
LED4
AD2
SPI_CSN
AD1
SPI_SDO
SPI_SDO
SPI_SDO
AD1
SDA
LED[0:15]
+3.3V +5V
R10 0 ohm
R1 1k
TP2
1
J10
HEADER5x2
2
4
6
8
10
1
3
5
7
9
L2
BLM18BD471SN1
J4
1 2
L3
BLM18BD471SN1
R3
10K
TP1
1
U1
PCA9955A/PCA9955B
REXT
1
AD0
2
AD1
3
AD2
4
OE
5
LED0
6
LED1
7
LED2
8
LED3
9
LED4
11
LED5
12
LED6
13
LED7
14
Vss
10
LED8 15
LED9 16
LED10 17
LED11 18
LED12 20
Vss 19
LED13 21
LED14 22
LED15 23
RESET 25
SCL/USCL 26
SDA/USDA 27
Vdd 28
Vss 24
R9
1k
J2
JUMPER3x2
1 2
3 4
5 6
R5
1.1K
L1 HI1206N101R-10 CON2
9-pin Female
1
2
3
4
5
6
7
8
9
R22
10K
CON1
9-pin Male
1
2
3
4
5
6
7
8
9
R18 0 ohm
CON3
5-pin Male
1
2
3
4
5
D1
LTST-C170GKT
R19 31.6K
J5
12
R14 0 ohm
R20 34.8K
CON4
HEADER 7x2/SM
1 2
34
5 6
7 8
910
11 12
13 14
AVR-M1608C080M1
VARISTOR
C6
10 uF
C2
10 uF
R12 34.8K
R15 31.6K
R21 0 ohm
R8 0 ohm
J8
1
2
3
J9
HEADER5x2
2
4
6
8
10
1
3
5
7
9
C7
0.01uF
R16 34.8K
R17 0 ohm
R2 1.5k
TP3
1
R6 2K
U2
PRTR5V0U2AX
GND
1
I/O1
2I/O2 3
VCC 4
C3
0.1uF
R4
1.1K
J3
1 2
J7
JUMPER4x2
1 2
34
5 6
78
J11
12
C5
10 uF
C1
10 uF
J1
1 2 3
C4
4.7 uF
R13 0 ohm
J6
12
R11 31.6K
TP4
1
R7 0 ohm

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PCA9955A/B demonstration board OM13483
Fig 6. PCA9955A/B demo board schematic (part B)
aaa-013944
4-white and 4-RGB LEDs connect to PCA9955A/B 16-channel outputs
(The LEDs supply voltage can be selected either internal +3.3V/+5V or external up to +20V)
External voltage input for LED supply
(Less or equal 20V and J13 is open)
RGB4
(R)
(G) (B)
LED13 short test
LED15 short test
LED14 short test
LED12 open test & ouput
current measurement
LED13 open test & ouput
current measurement
LED14 open test & ouput
current measurement
Notes:
Vf = 3.2V for White LED
Vf = 2.1V for Red LED
Vf = 3.2V for Green LED
Vf = 3.2V for Blue LED
Open/Short test only available for
first four channels LED[0:3] and
last four channels LED[12:15]
LED voltage select:
OPEN: use external voltage
1-2: internal +3.3V
2-3: internal +5V
LED15 open test & ouput
current measurement
LED12 short test
RGB4
(R)
(G) (B)
RGB4
(R)
(G) (B)
LED3 open test & ouput
current measurement
LED0 short test
RGB4
(R)
(G) (B)
LED1 short test
LED3 short test
LED2 short test
LED0 open test & ouput
current measurement
LED1 open test & ouput
current measurement
LED2 open test & ouput
current measurement
These serial resistors R23-R38 can change to
non-zero value for voltage switch PCA9955A/B
devices to adjust LED output current
LED0 + LED1
LED1+ LED2
LED[0:15]
+3.3V
+5V
LED0
LED1
LED2
LED3
LED4
LED5
LED6
LED7
LED8
LED9
LED10
LED11
LED12
LED13
LED14
LED15
LED[0:15]
+3.3V
+5V
C21
0.1nF
R29 0 ohm
J13
1
2
3
J25
1 2
R34 0 ohm
J26
1 2
R28 0 ohm
J31
1 2
RGB_LED3
LRTB_G6SF
A1
C2
A2 A3
C3
C1
R33 0 ohm
C11
0.1nF
R27 0 ohm
R32 0 ohm
C12
0.1nF
J12
12
J23
12
R31 0 ohm
C9
0.1nF
R23 0 ohm
WHT_LED3
LW E67C
J21
1 2
C16
0.1nF
WHT_LED4
LW E67C
R25 0 ohm
J15
1 2
RGB_LED1
LRTB_G6SF
A1
C2
A2 A3
C3
C1
C17
0.1nF
C13
0.1nF
C18
0.1nF
C14
0.1nF
R38 0 ohm
J27
1 2
J14
1 2
C8
10 uF
C15
0.1nF
RGB_LED2
LRTB_G6SF
A1
C2
A2 A3
C3
C1
C10
0.1nF
R37 0 ohm
RGB_LED4
LRTB_G6SF
A1
C2
A2 A3
C3
C1
C22
0.1nF
J22
1 2
R36 0 ohm
J18
12
J16
1 2
C23
0.1nF
R35 0 ohm
R24 0 ohm
J29
1 2
J17
12
R26 0 ohm
C24
0.1nF
J28
1 2
WHT_LED1
LW E67C
C19
0.1nF
J19
12
J24
HEADER 2
1
2
J30
1 2
R30 0 ohm
WHT_LED2
LW E67C
J32
12
C20
0.1nF
J20
HEADER 2
1
2

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PCA9955A/B demonstration board OM13483
7. OM13483 demonstration board main components
8. PCA9955A/B evaluation steps
The PCA9955A/B is controlled by Win-I2CUSB GUI in Expert mode, as shown in
Figure 7.
Connect the hardware as described in Section 4. All jumpers are in default setting and
device address is set to 0x02 on J7, J9 and J10 (set AD[0:2] = GND) for PCA9955A/B
demo board. When you have correctly installed the software and the demonstration board
hardware is connected and recognized by the computer, start the Win-I2CUSB Lite
Table 2. OM13483 demo board main components
Device Description Address/LED Location
PCA9955BTW 16-channel Fm+ I2C-bus
57 mA / 20 V constant current
LED driver
0x02h for I2C demo board
(default setting) U1
PRTR5V0U2AX ESD protection diode - U2
LW-E67C White LED 4 white LEDs WHT_LED[1:4]
LRTB_G6SG RGB LED 4 RGB LEDs RGB_LED[1:4]
LTST-C170GKT Green LED for PCA9955A/B
power supply either 3.3 V or
5 V indicator
1 green LED D1
Fig 7. Drop-down menu selection for Expert mode

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software. As shown in Figure 7, when the demonstration board hardware is correctly
connected to the USB port and the computer recognizes it, the message ‘Hardware
Detected’ is displayed on the bottom of the window.
Switched 3.3 V and 5.0 V power supplies are controlled through the ‘Options’ menu or by
double-clicking the 3.3 V or 5.0 V symbols on the bottom of the window. Power supplies
are disabled by default and must be enabled before using the I2C-bus devices on the
board. I2C-bus frequency is controlled through the ‘Options’ menu or by double-clicking
the frequency symbol on the bottom of the window.
8.1 PCA9955A/B blinking demo for all White and RGB LEDs
1. From the ‘Device’ drop-down menus select ‘Universal Modes’, and from the
subsequent drop-down menu select ‘Expert Mode’ as shown in Figure 7.
2. Copy the ‘PCA9955A/B WHT_RGB LEDs blinking demo i2c address = 0x02h’ text file
as shown below. From the ‘File’ drop-down menus select ‘Open’, and from the
‘open data file’ window select the ‘PCA9955A/B WHT_RGB LEDs blinking demo
i2c address = 0x02h’ text file.
Expert Mode Data File
00,Write,Yes,0,06,Comments: SW reset
02,Write,Yes,0,45,80,Comments: write IREFALL to 80h (225 uA x 128 = 28.8 mA per
channel)
02,Write,Yes,500,82,01,01,01,01,Comments: start write LEDOUTx register to turn on
white LEDs
02,Write,Yes,700,82,04,04,04,04,Comments: start write LEDOUTx register to turn on
red LEDs
02,Write,Yes,500,82,01,01,01,01,Comments: start write LEDOUTx register to turn on
white LEDs
02,Write,Yes,700,82,10,10,10,10,Comments: start write LEDOUTx register to turn on
green LEDs
02,Write,Yes,500,82,01,01,01,01,Comments: start write LEDOUTx register to turn on
white LEDs
02,Write,Yes,700,82,40,40,40,40,Comments: start write LEDOUTx register to turn on
blue LEDs
02,Write,Yes,300,82,01,00,00,00,Comments: start write LEDOUTx register to turn on
white LEDs
02,Write,Yes,300,82,00,05,00,00,Comments: start write LEDOUTx register to turn on
white, red LEDs
02,Write,Yes,300,82,00,00,51,00,Comments: start write LEDOUTx register to turn on
white, Blue_Green LEDs
02,Write,Yes,300,82,00,00,00,55,Comments: start write LEDOUTx register to turn on
white and RGB LEDs
02,Write,Yes,400,82,40,01,04,10,Comments: start write LEDOUTx register to turn on
white and RGB LEDs
02,Write,Yes,400,82,10,40,01,04,Comments: start write LEDOUTx register to turn on
white and RGB LEDs
02,Write,Yes,400,82,04,10,40,01,Comments: start write LEDOUTx register to turn on
white and RGB LEDs
02,Write,Yes,400,82,01,40,10,04,Comments: start write LEDOUTx register to turn on
white and RGB LEDs

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02,Write,Yes,0,81,21,FF,FF,FF,FF,Comments: start write 01h register to program the
DMBLNK=1 for blinking, LDRx=11 for group dimming/blinking controlled by
GRPPWM, GRPFREQ
02,Write,Yes,0,44,C0,Comments: write PWMALL register to set the PWMx=C0h 75% duty
cycles for individual LED
02,Write,Yes,2000,86,40,00,Comments: write GRPPWM=40h for duty cycle (ON/OFF ratio
in 25%) and GRPFREQ= 00h (67 ms for blinking period)
02,Write,Yes,2000,86,80,01,Comments: write GRPPWM=80h for duty cycle (ON/OFF ratio
in 50%) and GRPFREQ= 02h (131 ms for blinking period)
02,Write,Yes,2000,86,A0,02,Comments: write GRPPWM=C0h for duty cycle (ON/OFF ratio
in 62.5%) and GRPFREQ= 04h (196 ms for blinking period)
02,Write,Yes,2000,86,C0,03,Comments: write GRPPWM=FFh for duty cycle (ON/OFF ratio
in 75%) and GRPFREQ= 06h (262 ms for blinking period)
00,Write,Yes,0,06,Comments: SW reset
Sequence:01,02,03,04,05,06,07,08,09,10,11,12,13,14,15,16,17,18,19,20,21,22,23
3. After opening the ‘PCA9955A/B WHT_RGB LEDs blinking demoi2c address = 0x02h’
text file, the Win-I2CUSB GUI in Expert mode screen will be displayed as shown in
Figure 8.
4. Click the ‘Send All’ button. All the valid messages on the screen is sent in order of the
row number (Msg #). The action is performed one time.
Fig 8. Message data in Expert mode to demonstrate all White and RGB LEDs for
blinking

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PCA9955A/B demonstration board OM13483
8.2 Test of LED open or short error detection
The PCA9955A/B can detect an LED open or short condition at its open-drain LED
outputs. Users recognize these faults by reading the status of a pair of error bits (ERRx) in
error flag registers (EFLAGn) for each channel.
The user can poll the ERROR status bit (bit 6 in MODE2 register) to check if there is a
fault condition in any of the 16 channels. The EFLAGn registers can then be read to
determine which channels are at fault and the type of fault in those channels.
1. Copy the ‘PCA9955A/B Open or Short test’ text file as shown below. From the ‘File’
drop-down menus select ‘Open’, and from the ‘open data file’ window select the
‘PCA9955A/B Open or Short test’ text file.
Expert Mode Data File
00,Write,Yes,5,06,Comments: software reset
02,Write,Yes,0,98,80,80,Comments: set current to 50% of max in IREF0/IREF1
02,Write,Yes,50,02,05,Comments: set LED0 and LED1 are fully ON
02,Write,Yes,1,01,11,Comments: Clear all error status bits in EFLAGn registers by
writing bit4=1 in MODE2
02,Read,Yes,0,01,Comments: read ERROR status (bit6) in MODE2
02,Write,Yes,0,46,Comments: set EFLAG0 register address
02,Read,Yes,0,00,Comments: Read EFLAG0 status (bit1/0 for LED 0 and bit 3/2 for
LED1 error status)
02,Write,Yes,1,01,11,Comments: Clear all error status bits in EFLAGn registers by
writing bit4=1 in MODE2
02,Write,Yes,0,98,00,00,Comments: set output current to zero in IREF0/IREF1
Sequence:01,02,03,04,05,06,07,08,09
2. After opening the ‘PCA9955A/B Open or Short test’ text file, the Win-I2CUSB GUI in
Expert mode screen will be displayed as shown in Figure 9.
3. Click the ‘Send All’ button. All the valid messages on the screen is sent in order of the
row number (Msg #). The action is performed one time.
4. To verify the read data on message line 5 for ERROR status and line 7 for EFLAG
status.
5. To open the J12 and J16 for open-circuit test on LED0 and LED1, repeat steps 3and
4to find the error report in message line 5 and line 7.
6. To short the J15 and J17 for short-circuit test on LED0 and LED1, repeat steps 3and
4to find the error report in message line 5 and line 7.

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PCA9955A/B demonstration board OM13483
Fig 9. Example of Open or Short-circuit test for LED0 and LED1

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PCA9955A/B demonstration board OM13483
9. PCA9955A/B evaluation steps with Fm+ development board
The PCA9955A/B is controlled by Fm+ development board GUI in Expert mode, as shown
in Figure 10.
Connect the hardware as described in Section 4.3. All jumpers are in default setting and
device address is set to 0x02 on J7, J9 and J10 (set AD[0:2] = GND) for PCA9955A/B
demo board. When you have correctly installed the software and the demonstration board
hardware is connected and recognized by the computer, start the Fm+ development
board software. As shown in Figure 10, when the demonstration board hardware is
correctly connected to the USB port and the computer recognizes it, the message
‘USB-I2C Hardware Detected’ is displayed on the bottom of the window.
Fig 10. Select the Expert mode from Fm+ development board GUI

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PCA9955A/B demonstration board OM13483
9.1 PCA9955A/B blinking and gradation demo for all LEDs
1. From the ‘Device’ drop-down menus select ‘Expert Modes’ as shown in Figure 10.
2. Copy the ‘PCA9955A/B WHT_RGB LEDs blinking & gradation demo i2c address =
0x02h’ text file as shown below. From the ‘File’ drop-down menus select ‘Open’, and
from the ‘open data file’ window to select the ‘PCA9955A/B WHT_RGB LEDs blinking
& gradation demo i2c address = 0x02h’ text file.
Expert Mode Data File
00,Write,Yes,0,06,Comments: SW reset
02,Write,Yes,0,45,80,Comments: write IREFALL to 80h (225uA x 128 = 28.8mA per
channel)
02,Write,Yes,500,82,01,01,01,01,Comments: start write LEDOUTx register to turn on
white LEDs
02,Write,Yes,700,82,04,04,04,04,Comments: start write LEDOUTx register to turn on
red LEDs
02,Write,Yes,500,82,01,01,01,01,Comments: start write LEDOUTx register to turn on
white LEDs
02,Write,Yes,700,82,10,10,10,10,Comments: start write LEDOUTx register to turn on
green LEDs
02,Write,Yes,500,82,01,01,01,01,Comments: start write LEDOUTx register to turn on
white LEDs
02,Write,Yes,700,82,40,40,40,40,Comments: start write LEDOUTx register to turn on
blue LEDs
02,Write,Yes,300,82,01,00,00,00,Comments: start write LEDOUTx register to turn on
white LEDs
02,Write,Yes,300,82,00,05,00,00,Comments: start write LEDOUTx register to turn on
white, red LEDs
02,Write,Yes,300,82,00,00,51,00,Comments: start write LEDOUTx register to turn on
white, Blue_Green LEDs
02,Write,Yes,300,82,00,00,00,55,Comments: start write LEDOUTx register to turn on
white and RGB LEDs
02,Write,Yes,400,82,40,01,04,10,Comments: start write LEDOUTx register to turn on
white and RGB LEDs
02,Write,Yes,400,82,10,40,01,04,Comments: start write LEDOUTx register to turn on
white and RGB LEDs
02,Write,Yes,400,82,04,10,40,01,Comments: start write LEDOUTx register to turn on
white and RGB LEDs
02,Write,Yes,400,82,01,40,10,04,Comments: start write LEDOUTx register to turn on
white and RGB LEDs
02,Write,Yes,0,81,21,FF,FF,FF,FF,Comments: start write 01h register to program the
DMBLNK=1 for blinking, LDRx=11 for group dimming/blinking controlled by
GRPPWM, GRPFREQ
02,Write,Yes,0,44,C0,Comments: write PWMALL register to set the PWMx=C0h 75% duty
cycles for individual LED
02,Write,Yes,2000,86,40,00,Comments: write GRPPWM=40h for duty cycle (ON/OFF ratio
in 25%) and GRPFREQ= 00h (67mS for blinking period)
02,Write,Yes,2000,86,80,01,Comments: write GRPPWM=80h for duty cycle (ON/OFF ratio
in 50%) and GRPFREQ= 02h (131mS for blinking period)
02,Write,Yes,2000,86,A0,02,Comments: write GRPPWM=C0h for duty cycle (ON/OFF ratio
in 62.5%) and GRPFREQ= 04h (196mS for blinking period)

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02,Write,Yes,2000,86,C0,03,Comments: write GRPPWM=FFh for duty cycle (ON/OFF ratio
in 75%) and GRPFREQ= 06h (262 mS for blinking period)
00,Write,Yes,0,06,Comments: write SW reset
02,Write,Yes,0,81,01,Comments: set linear curve
02,Write,Yes,0,82,05,05,05,05,Comments: set LDR= 01, turn white & red LED ON
02,Write,Yes,1,A8,C1,47,C9,78,00,00,00,00,00,00,00,00,00,00,00,00,33,33,00,00,00,
00,03,Comments: set group0 in continuous mode, IREF_GRP=120x225=27mA,
60-step, 64ms & 450ua per step, ramp up/dn time 3.9s & hold on/off (0.25s)
02,Write,Yes,8200,45,01,Comments: set IREFALL not 0 to enable LED outputs
00,Write,Yes,0,06,Comments: write SW reset
02,Write,Yes,1,81,05,Comments: set exponential curve
02,Write,Yes,0,82,11,11,11,11,Comments: set LDR= 01, turn white & green LED ON
02,Write,Yes,1,A8,C1,47,C9,78,00,00,00,00,00,00,00,00,00,00,00,00,55,55,00,00,00,
00,03,Comments: set group0 in continuous mode, IREF_GRP=240x225=27mA,
60-step, 64ms &450ua per step, ramp up/dn time 3.9s & hold on/off (0.25s)
02,Write,Yes,8200,45,01,Comments: set IREFALL not 0 to enable LED outputs
00,Write,Yes,0,06,Comments: write SW reset
02,Write,Yes,1,81,05,Comments: set exponential curve
02,Write,Yes,0,82,41,41,41,41,Comments: set LDR= 01, turn white & blue LED ON
02,Write,Yes,1,A8,C1,47,C9,78,00,00,00,00,00,00,00,00,00,00,00,00,99,99,00,00,00,
00,03,Comments: set group0 in continuous mode, IREF_GRP=240x225=27mA,
60-step, 64ms &450ua per step, ramp up/dn time 3.9s & hold on/off (0.25s)
02,Write,Yes,8200,45,01,Comments: set IREFALL not 0 to enable LED outputs
00,Write,Yes,0,06,Comments: write SW reset
Sequence:01,02,03,04,05,06,07,08,09,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,
25,26,27,28,29,30,31,32,33,34,35,36,37,38
3. After opening the ‘PCA9955A/B WHT_RGB LEDs blinking & gradation demo i2c
address = 0x02h’ text file, the ‘NXP Fm+ Board GUI’ in Expert mode screen is
displayed as shown in Figure 11.
4. Click the ‘Send All’ button. All the valid messages on the screen will be sent in the
order of the row number (Msg #). The action will be performed one time.