c - How to make timer0 use a prescaler of 1:64 in 16 bit mode? -

i not have understanding timers, trying change timer0 make use prescaler of 1:64 in 16 bit mode? got timer code microchip , using 8 bit mode no prescaler. download files

this portion of code suspect has deal prescalers.

tmr_con = 0b00000000 | clock_divider_setting; tmr_ip = 1; tmr_if = 0; tmr_ie = 1; tmr_on = 1; 

this info pic18f87j11 datasheet prescalers

t0ps2:t0ps0: timer0 prescaler select bits    111 = 1:256 prescale value 110 = 1:128 prescale value 101 = 1:64   prescale value 100 = 1:32   prescale value 011 = 1:16   prescale value 010 = 1:8     prescale value 001 = 1:4     prescale value 000 = 1:2     prescale value 

i assuming use 1:64 prescalar, code must changed following, correct?

tmr_con = 0b00000101 | clock_divider_setting; tmr_ip = 1; tmr_if = 0; tmr_ie = 1; tmr_on = 1; 

now, please tell me how change 8 bit mode 16 bit mode ? said beginner, please explain things level of understanding.

i appreciate in advance!

from microchip datasheet:

t0con: timer0 control register     bit 7 tmr0on: timer0 on/off control bit   1 = enables timer0   0 = stops timer0 bit 6 t08bit: timer0 8-bit/16-bit control bit   1 = timer0 configured 8-bit timer/counter   0 = timer0 configured 16-bit timer/counter bit 5 t0cs: timer0 clock source select bit   1 = transition on t0cki pin input edge   0 = internal clock (fosc/4) bit 4 t0se: timer0 source edge select bit   1 = increments on high-to-low transition on t0cki pin   0 = increments on low-to-high transition on t0cki pin bit 3 psa: timer0 prescaler assignment bit   1 = timer0 prescaler not assigned; timer0 clock input bypasses prescaler   0 = timer0 prescaler assigned; timer0 clock input comes prescaler output bit 2-0 t0ps<2:0>: timer0 prescaler select bits   111 = 1:256 prescale value   110 = 1:128 prescale value   101 = 1:64 prescale value   100 = 1:32 prescale value   011 = 1:16 prescale value   010 = 1:8 prescale value   001 = 1:4 prescale value   000 = 1:2 prescale value 

1. clear t08bit bit select 16bit mode.
2. clear t0cs bit if wont internal clock (fosc/4) timer0/prescaler input.
3. clear psa bit select prescaler.
4. set t0ps<2:0> select prescaler rate.
5. set tmr0on 1 ro enable timer0.

this equal:

t0con =b'10000nnn' //where nnn prescaler value 

if need interrupts on timer0 overflow enable timer0 interrupt bits (gie/gieh, peie/giel, tmr0ie, tmr0if).