PCA9629PW,118 NXP Semiconductors, PCA9629PW,118 Datasheet - Page 10

• Manufacturer Part Number: PCA9629PW,118
• Description: Motor / Motion / Ignition Controllers & Drivers I2C-bus Stepper motor controller
• Manufacturer: NXP Semiconductors
• Type: Stepper Motor Controllerr

Specifications of PCA9629PW,118

• Rohs: yes
• Product: Stepper Motor Controllers / Drivers
• Operating Supply Voltage: 4.5 V to 5.5 V
• Supply Current: 6 mA
• Mounting Style: SMD/SMT
• Package / Case: TSSOP-16
• Factory Pack Quantity: 2500

NXP Semiconductors
PCA9629
Product data sheet
7.3.4.1 WDTOI — WatchDog Time-Out Interval register
7.3.4 Watchdog timer
The purpose of the watchdog timer is to recover the PCA9629 if the system it is used in
enters an erroneous state. When the timer times out, the watchdog generates an interrupt
to the host controller and, if programmed for reset, resets PCA9629 if the user program
fails to ‘feed’ the watchdog. To feed the watchdog, the user simply addresses the
PCA9629 ([START + slave address + START] or [START + slave address + STOP]) within
the watchdog time-out interval. Only this sequence resets the watchdog.
Watchdog timer features:
The watchdog timer should be used in the following manner:
The watchdog time-out interval should be programmed in this register. The default value
is FFh, which indicates a 255 second time-out interval. The smallest value for the time-out
interval is 01h, which indicates a one-second time-out interval. Watchdog operation
cannot be enabled with a zero second time-out interval. If user writes a zero value to this
register, the timer does not start.
Table 9.
Legend: * default value.
Address
05h
•
•
•
•
•
•
•
•
•
Can be programmed to reset the PCA9629 to POR state if it is not periodically
addressed
Enabled by software, but requires a hardware reset or a watchdog reset to be
disabled
Flag to indicate watchdog reset
Programmable 8-bit timer with internal prescaler
Selectable time period from one second to 255 seconds
Set the time-out interval value in WDTOI register
Set the mode of operation (interrupt only or interrupt and reset) and enable the
watchdog using the WDCNTL register
Watchdog should be fed by periodically addressing PCA9629 before the watchdog
timer underflows to prevent reset/interrupt
Watchdog control register, WDCNTL, can be read at any time to determine the status
of the watchdog operation
WDTOI - Watchdog time-out interval register (address 05h) bit description
Register
WDTOI
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 29 February 2012
Bit
7:0
Access
R/W
Value
FFh*
Fm+ I
Description
Watchdog time-out interval
2
C-bus stepper motor controller
PCA9629
© NXP B.V. 2012. All rights reserved.
10 of 51