Watchdog Timer
UG0331 User Guide Revision 15.0
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20
Watchdog Timer
The watchdog timer is an advanced peripheral bus (APB) slave that guards against the system crashes
by requiring regular service by the Cortex-M3 processor or by a bus master in the field programmable
gate array (FPGA) fabric.
20.1
Features
The watchdog timer has following features:
•
A 32-bit timer counts down from a preset value to zero, then performs one of the following user-
configurable operations: If the counter is not refreshed, it will time out and either cause a system
reset or generate an interrupt to the processor.
•
The watchdog timer counter is halted when the Cortex-M3 processor enters the debug state.
•
The watchdog timer can be configured to generate a wake up interrupt when the Cortex-M3 is in
sleep mode.
As shown in the following figure, the watchdog timer is connected to the AHB bus matrix through the
APB_0 interface.
Figure 267 •
Microcontroller Subsystem Showing Watchdog Timer
AHB Bus Matrix
eSRAM_0
System
Controller
Cache
Controller
S
D
IC
ARM Cortex-M3
Processor
S
D
I
MSS DDR
Bridge
PDMA
MS6
MM3
AHB To AHB Bridge with Address Decoder
USB OTG
HPDMA
MDDR
APB_0
SYSREG
Triple Speed
Ethernet MAC
FIC_0
MM4
MS4
MS2
MS3
MS0
MS5
MS1
MM5
MM6
MM7
MM8
MM2
MM1
MM0
MM9
IDC
D/S
eNVM_0
eNVM_1
eSRAM_1
FIC_2 (Peripheral
Initialization)
APB_1
MMUART_0
SPI_0
I2C_0
PDMA
Configuration
WATCHDOG
FIIC
TIMERx2
MMUART_1
SPI_1
I2C_1
GPIO
CAN
RTC
COMM_BLK
FIC_1
MSS_F
IC
MS6_USB
MS5_MAC
MS5_SR
MS5_APB0
MS5_FIC2
MS5_APB1