pca9632 NXP Semiconductors, pca9632 Datasheet - Page 13

• Manufacturer Part Number: pca9632
• Description: Pca9632 4-bit Fm I?c-bus Low Power Led Driver
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA9632_1
Objective data sheet
7.5 Software Reset
7.6 Using the PCA9632 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 PCA9632 does not initiate a reset of its registers. This
happens only when the format of the SWRST Call sequence is not correct.
The PCA9632 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 PCA9632 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 PCA9632 acknowledges this value only. If byte 1 is not equal to
b. Byte 2 = 5Ah: the PCA9632 acknowledges this value only. If byte 2 is not equal to
If more than 2 bytes of data are sent, the PCA9632 does not acknowledge any more.
correctly acknowledged, the master sends a STOP command to end the SWRST Call:
the PCA9632 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.
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 PCA9632 (at any time) as
A5h, the PCA9632 does not acknowledge it.
5Ah, then the PCA9632 does not acknowledge it.
2
C-bus master.
2
C-bus master.
Rev. 01 — 28 September 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.
4-bit Fm+ I
2
C-bus command. To be performed
BUF
2
C-bus low power LED driver
).
2
C-bus to be reset to
PCA9632
© NXP B.V. 2007. All rights reserved.
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