System Timer
UG0331 User Guide Revision 15.0
614
19
System Timer
The SmartFusion2 system timer (hereinafter referred as timer) consists of two programmable 32-bit
decrementing counters that generate interrupts to the Cortex-M3 processor and FPGA fabric. The two
32-bit timers are identical. X is used as a placeholder for 1, 2, or 64 in register descriptions. It indicates
Timer 1, Timer 2, or Timer 64.
19.1
Features
The timer has the following features:
•
Three count modes: One-shot and Periodic
•
Decrementing 32-bit counters
•
Two 32-bit timers can be concatenated to create a 64-bit timer.
•
Option to enable or disable the interrupt requests when timer reaches zero.
•
Controls to start, stop, and reset the timer
The following figure shows details of the MSS. Timer peripherals are connected to the AHB bus matrix
through the APB_0 interface.
Figure 261 •
MSS Showing Timer Peripherals
19.2
Functional Description
This section provides detailed description of the timer.
19.2.1
Architecture Overview
The timer is an APB_0 slave that provides two programmable, interrupt generating, 32-bit decrementing
counters, as shown in the following figure.
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