© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
User manual
Rev. 01 — 15 August 2005
251
Philips Semiconductors
UM10139
Volume 1
Chapter 15: TIMER0 and TIMER1
15.6 Example timer operation
shows a timer configured to reset the count and generate an interrupt on match.
The prescaler is set to 2 and the match register set to 6. At the end of the timer cycle
where the match occurs, the timer count is reset. This gives a full length cycle to the
match value. The interrupt indicating that a match occurred is generated in the next clock
after the timer reached the match value.
shows a timer configured to stop and generate an interrupt on match. The
prescaler is again set to 2 and the match register set to 6. In the next clock after the timer
reaches the match value, the timer enable bit in TCR is cleared, and the interrupt
indicating that a match occurred is generated.
Table 244: External match control
EMR[11:10], EMR[9:8],
EMR[7:6], or EMR[5:4]
Function
00
Do Nothing.
01
Clear the corresponding External Match bit/output to 0 (MATn.m pin is LOW if pinned out).
10
Set the corresponding External Match bit/output to 1 (MATn.m pin is HIGH if pinned out).
11
Toggle the corresponding External Match bit/output.
Fig 56. A timer cycle in which PR=2, MRx=6, and both interrupt and reset on match are enabled
PCLK
Prescale
counter
Iterrupt
Timer
counter
Timer counter
reset
2
2
2
2
0
0
0
0
1
1
1
1
4
5
6
0
1
Fig 57. A timer cycle in which PR=2, MRx=6, and both interrupt and stop on match are enabled
PCLK
Prescale
counter
Iterrupt
Timer
counter
TCR[0]
(counter enable)
2
2
0
0
1
4
5
6
1
0