Samsung S3C9228/P9228 Microcassette Recorder User Manual


 
S3C9228/P9228 TIMER 1
11-7
FUNCTION DESCRIPTION
Interval Timer Function (Timer A and Timer B)
The timer A and B module can generate an interrupt: the timer A match interrupt (TAINT) and the timer B match
interrupt (TBINT).
The timer A match interrupt pending condition (INTPND2.0) and the timer B match interrupt pending condition
(INTPND2.1) must be cleared by software in the application's interrupt service by means of writing a "0" to the
INTPND2.0 and INTPND2.1 interrupt pending bit.
Even though TAINT and TBINT are disabled, the application's service routine can detect a pending condition of
TAINT and TBINT by the software and execute it's sub-routine. When this case is used, the TAINT and TBINT
pending bit must be cleared by the application sub-routine by writing a "0" to the corresponding pending bit
INTPND2.0 and INTPND2.1.
In interval timer mode, a match signal is generated when the counter value is identical to the values written to
the timer A or timer B reference data registers, TADATA or TBDATA. The match signal generates corresponding
match interrupt and clears the counter.
If, for example, you write the value 20H to TADATA and 0EH to TACON, the counter will increment until it
reaches 20H. At this point, the timer A interrupt request is generated, the counter value is cleared, and counting
resumes and you write the value 10H to TBDATA, "0" to TACON.7, and 0EH to TBCON, the counter will
increment until it reaches 10H. At this point, TB interrupt request is generated, the counter value is cleared and
counting resumes.