pca9635 NXP Semiconductors, pca9635 Datasheet - Page 16

• Manufacturer Part Number: pca9635
• Description: Pca9635 16-bit Fm I2c-bus Led Driver
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA9635_5
Product data sheet
7.6 Software Reset
7.7 Using the PCA9635 with and without external drivers
The Software Reset Call (SWRST Call) allows all the devices in the I
the power-up state value through a specific formatted I
correctly, it implies that the I
bus.
The SWRST Call function is defined as the following:
The I
a ‘SWRST Call Abort’. The PCA9635 does not initiate a reset of its registers. This
happens only when the format of the SWRST Call sequence is not correct.
The PCA9635 LED output drivers are 5.5 V only tolerant and can sink up to 25 mA at 5 V.
If the device needs to drive LEDs to a higher voltage and/or higher current, use of an
external driver is required.
1. A START command is sent by the I
2. The reserved SWRST I
3. The PCA9635 device(s) acknowledge(s) after seeing the SWRST Call address
4. Once the SWRST Call address has been sent and acknowledged, the master sends
5. Once the right 2 bytes (SWRST data byte 1 and byte 2 only) have been sent and
•
•
sent by the I
‘0000 0110’ (06h) only. If the R/W bit is set to ‘1’ (read), no acknowledge is returned to
the I
2 bytes with 2 specific values (SWRST data byte 1 and byte 2):
a. Byte 1 = A5h: the PCA9635 acknowledges this value only. If byte 1 is not equal to
b. Byte 2 = 5Ah: the PCA9635 acknowledges this value only. If byte 2 is not equal to
If more than 2 bytes of data are sent, the PCA9635 does not acknowledge any more.
correctly acknowledged, the master sends a STOP command to end the SWRST Call:
the PCA9635 then resets to the default value (power-up value) and is ready to be
addressed again within the specified bus free time (t
INVRT bit (MODE2 register) can be used to keep the LED PWM control firmware the
same (PWMx and GRPPWM values directly calculated from their respective formulas
and the LED output state determined by LEDOUT register value) independently of the
type of external driver. This bit allows LED output polarity inversion/non-inversion only
when OE = 0.
OUTDRV bit (MODE2 register) allows minimizing the amount of external components
required to control the external driver (N-type or P-type device).
2
C-bus master must interpret a non-acknowledge from the PCA9635 (at any time) as
A5h, the PCA9635 does not acknowledge it.
5Ah, then the PCA9635 does not acknowledge it.
2
C-bus master.
2
C-bus master.
Rev. 05 — 22 March 2007
2
2
C-bus address ‘0000 011’ with the R/W bit set to ‘0’ (write) is
C-bus is functional and that there is no device hanging the
2
C-bus master.
2
C-bus command. To be performed
BUF
16-bit Fm+ I
).
2
C-bus to be reset to
PCA9635
2
© NXP B.V. 2007. All rights reserved.
C-bus LED driver
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