Samsung S5PC110 Manual page 747

S5PC110_UM
To generate interrupt at intervals 3cycle of XpwmTOUTn, set TCNTBn, TCMPBn and TCON register as shown in
Figure 1-3.
Steps to generate interrupt:
1. Set TCNTBn=3 and TCMPBn=1.
2. Set auto-reload=1 and manual update=1.
If manual update bit is 1, then TCNTBn and TCMPBn values are loaded to TCNTn and TCMPn.
3. Set TCNTBn=2 and TCMPBn=0 for the next operation. 4. Set auto-reload=1 and manual update=0.
If you set manual update=1 at this time, TCNTn is changed to 2 and TCMP is changed to 0.
Therefore, interrupt is generated at interval two-cycle instead of three-cycle.
You must set auto-reload=1 automatically for the next operation.
5. Set start = 1 for starting the operation. Then TCNTn is down counting.
If TCNTn is 0, interrupt is generated and if auto-reload is enable, TCNTn is loaded 2 (TCNTBn value) and
TCMPn is loaded 0 (TCMPn value).
6. TCNTn is down counting before it stops.
1 PULSE WIDTH MODULATION TIMER
1-6