25.4.2.2 Synchronous External Counter Initialization Steps
The following steps must be performed to configure the timer for Synchronous Counter mode:
- Clear the TON Control bit (TxCON[15]
=
0
) to disable the timer. - Set the TCS Control bit (TxCON[1] =
1
) to enable the TxCK pin clock selection. - Set the TSYNC Control bit (TxCON[2] =
1
) to enable TxCK pin clock synchronization. - Select the desired timer input clock prescale using TCKPS[1:0] bits in TxCON register.
- Load/clear the Timer register, TMRx.
- Load the Timer Period register, PRx, with the desired 32-bit match value.
- If interrupts are used:
- Clear the TxIF Interrupt Flag bit in the IFSx register.
- Configure the Interrupt Priority Levels in the IPCx register.
- Set the TxIE Interrupt Enable bit in the IECx register.
- Set the ON Control bit (TxCON[15] =
1
) to enable the timer.
Synchronous External Counter Example Code
T1CON = 0x0; // Stop timer and clear control register
T1CON = 0x00000106; // Set prescaler at 1:1, external clock source
TMR1 = 0x0; // Clear timer register
PR1 = 0xFFFFFFFF; // Load period register
T1CONbits.ON = 1; // Start timer