MSC8113 Reference Manual, Rev. 0
4-4
Freescale Semiconductor
System Interface Unit (SIU)
4.1.2 Timers Clock
The two SIU timers (the time counter and the periodic interrupt timer) use the same clock source,
TIMERSCLK
, which is derived from several sources, as described in Figure 4-3.
Refer to Section 22.1, Timers Programming Model, for details on timer programming. For proper
time counter operation, you must ensure that the frequency of
TIMERSCLK
for TMCNT is
8,192 Hz by properly selecting the clock and programming the timer and the prescaler control
bits in the Time Counter Status and Control Register (TMCNTSC[TCF]) and periodic interrupt
status and control register (PISCR[PTF]).
4.1.3 Time Counter (TMCNT)
TMCNT is a 32-bit counter that is clocked by
TIMERSCLK
. It indicates time-of-day for the
operating system and application software. The counter is reset to zero on
PORESET
or a hard
reset but is unaffected by a soft reset. Software initializes the time counter; you should set the
TIMERSCLK
frequency to 8,192 Hz, as explained in Section 4.1.2. TMCNT can be programmed to
generate a maskable interrupt when the time value matches the value programmed in its
associated alarm register. The interrupt is generated on the last TMCNT clock before it
transitions to a value greater than the alarm register. It can also be programmed to generate an
interrupt every second. The TMCNTSC enables or disables the various timer functions and
reports the interrupt source. Figure 4-4 shows a block diagram of TMCNT, which is described on
page 4-27 in Section 4.2.1, System Configuration and Protection Registers.
Figure 4-3. Timers Clock Generation
Divide by 512
Divide by 4
PISCR[PTF]
TMCNTSC[TCF]
GPIO30
TIMERSCLK for TMCNT
TIMERSCLK for PIT
Select external clock
and/or Timer programming to yield
either 4 MHz or 32 KHz at this point.
Timer Port
Timer A6
System
Clock
Timer
Programming
Programming
Default
Dedicated
Timer Port
Summary of Contents for MSC8113
Page 1: ...MSC8113 Reference Manual Tri Core 16 Bit Digital Signal Processor MSC8113RM Rev 0 May 2008 ...
Page 20: ...MSC8113 Reference Manual Rev 0 xx Freescale Semiconductor Contents ...
Page 28: ...MSC8113 Reference Manual Rev 0 xxviii Freescale Semiconductor ...
Page 56: ...MSC8113 Reference Manual Rev 0 1 28 Freescale Semiconductor MSC8113 Overview ...
Page 76: ...MSC8113 Reference Manual Rev 0 2 20 Freescale Semiconductor SC140 Core Overview ...
Page 134: ...MSC8113 Reference Manual Rev 0 4 30 Freescale Semiconductor System Interface Unit SIU ...
Page 168: ...MSC8113 Reference Manual Rev 0 6 18 Freescale Semiconductor Boot Program ...
Page 180: ...MSC8113 Reference Manual Rev 0 7 12 Freescale Semiconductor Clocks ...
Page 260: ...MSC8113 Reference Manual Rev 0 8 80 Freescale Semiconductor Memory Map ...
Page 300: ...MSC8113 Reference Manual Rev 0 9 40 Freescale Semiconductor Extended Core ...
Page 304: ...MSC8113 Reference Manual Rev 0 10 4 Freescale Semiconductor MQBus and M2 Memory ...
Page 308: ...MSC8113 Reference Manual Rev 0 11 4 Freescale Semiconductor SQBus ...
Page 590: ...MSC8113 Reference Manual Rev 0 17 46 Freescale Semiconductor Interrupt Processing ...
Page 614: ...MSC8113 Reference Manual Rev 0 18 24 Freescale Semiconductor Debugging ...
Page 622: ...MSC8113 Reference Manual Rev 0 19 8 Freescale Semiconductor Internal Peripheral Bus IPBus ...
Page 724: ...MSC8113 Reference Manual Rev 0 21 32 Freescale Semiconductor UART ...
Page 920: ...MSC8113 Reference Manual Rev 0 25 150 Freescale Semiconductor Ethernet Controller ...
Page 1171: ...MSC8113 Reference Manual Rev 0 Freescale Semiconductor C 61 EF wait_rts P 01077FFC 9F rts 71 ...
Page 1172: ...MSC8113 Reference Manual Rev 0 C 62 Freescale Semiconductor MSC8113 Boot Code ...
Page 1202: ...MSC8113 Reference Manual Rev 0 Index 30 Freescale Semiconductor Index ...