The CS bits select the clock source for Timer1. These bits allow the selection of several possible synchronous and asynchronous clock sources. The table below lists the clock source selections.
| CS | Clock Source | |||
|---|---|---|---|---|
| Timer1 | Timer3 | Timer5 | Timer7 | |
| 1111-1101 | Reserved | Reserved | Reserved | Reserved |
| 1100 | TMR7 overflow | TMR7 overflow | TMR7 overflow | Reserved |
| 1011 | TMR5 overflow | TMR5 overflow | Reserved | TMR5 overflow |
| 1010 | TMR3 overflow | Reserved | TMR3 overflow | TMR3 overflow |
| 1001 | Reserved | TMR1 overflow | TMR1 overflow | TMR1 overflow |
| 1000 | TMR0 overflow | TMR0 overflow | TMR0 overflow | TMR0 overflow |
| 0111 | CLKREF | CLKREF | CLKREF | CLKREF |
| 0110 | SOSC | SOSC | SOSC | SOSC |
| 0101 | MFINTOSC (500 kHz) | MFINTOSC (500 kHz) | MFINTOSC (500 kHz) | MFINTOSC (500 kHz) |
| 0100 | LFINTOSC | LFINTOSC | LFINTOSC | LFINTOSC |
| 0011 | HFINTOSC | HFINTOSC | HFINTOSC | HFINTOSC |
| 0010 | Fosc | Fosc | Fosc | Fosc |
| 0001 | Fosc/4 | Fosc/4 | Fosc/4 | Fosc/4 |
| 0000 | T1CKIPPS | T3CKIPPS | T5CKIPPS | T7CKIPPS |