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Texas Instruments MSC1210 User Manual

Page 68

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System Timers

7-4

7.2

System Timers

In addition to the standard 8052 timers to be described in Chapter 8, the
MSC1210 includes the following system timers, both of which are capable of
triggering an auxiliary interrupt (for more on interrupts, see chapter 10):

-

Microseconds Timer: set via the USEC (FB

H

) SFR, and is used to configure

the flash writing timing and also used by the PWM module.

-

Milliseconds Timer: set via the MSECH (FD

H

) and MSECL (FC

H

) SFRs, and

is used as a base to configure the flash erase timing, as well as the millisec-
onds interrupt, and also as a base for the seconds interrupt and the watchdog
timer.

The MSC1210 timers are illustrated in Figure 7−2. The SYS Clock is the signal
that comes from the oscillator or other timing input. This signal is used as the
input for all of the part’s timing logic, including the following timing circuits:

-

SPI I/O (chapter 13)

-

PWM/Tone generation (chapter 11).

-

Flash erase/write (chapter 15).

-

Milliseconds/Seconds/Watchdog interrupts (chapter 7, 14).

-

A/D conversion timing (chapter 12)

-

Standard 8052 timers 0, 1, and 2 (chapter 8).