NXP Semiconductors PCA9955BTW-ARD, Руководство пользователя, Страница: 22 / 38

NXP Semiconductors
UM11761
PCA9955BTW-ARD evaluation board
• REXT Settings selects the maximum current delivered by the LED: 20 mA (default
value) or 50 mA.
• OE
controls the OE input of the DUT.
• I2C Frequency displays the I2C-bus clock frequency. The drop-down box allows the
selection of three values: 100 kHz (default value), 400 kHz and 1 MHz.
Clicking the Set all button at the bottom of the section causes the selected values to be
set in the DUT internal registers. Clicking Reset Chip returns the internal registers to
their default values.
General Setting
The displayed parameters in the section, belongs to internal registers “MODE1” (00h),
”MODE2” (01h), and “OFFSET” (3Fh). Table 6 indicates the register address and bit
level for each parameter under General Settings section. See the PCA9955B datasheet
details regarding the “MODE1”, “MODE2”, and “OFFSET” registers.
Parameter Register name Reg. addr. (HEX) Bit Symbol / Description Remarks
LED All Call I2C-bus MODE1 00h 0 ALLCALL Read / Write
I2C-bus Subaddress 3 MODE1 00h 1 SUB3 Read / Write
I2C-bus Subaddress 2 MODE1 00h 2 SUB2 Read / Write
I2C-bus Subaddress 1 MODE1 00h 3 SUB1 Read / Write
Sleep MODE1 00h 4 SLEEP Read / Write
Auto-Incremental bit0 MODE1 00h 5 AI0 Read / Write
Auto-Incremental bit1 MODE1 00h 6 AI1 Read / Write
Auto-Increment MODE1 00h 7 AIF Read only
Gradation control MODE2 01h 2 EXP_EN Read / Write
Output Change MODE2 01h 3 OCH Read / Write
Group Control MODE2 01h 5 DMBLNK Read / Write
7:4 Not Used Read only
Offset OFFSET 3Fh
3:0 LEDn out delay offset factor Read / Write
Clear Errors MODE2 01h 4 CLDERR Write only
Table 6. The parameters under the General Settings section
Set the values for each parameter and click the Write button to update the PCA9955B
mode registers with the desired configuration. The Read button brings back the data from
the mode register to GUI interface.
The status bar located in the bottom side of the interface, shows the connection status
between the PC and the EVK.
UM11761 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2022. All rights reserved.
User manual Rev. 1.0 — 18 March 2022
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