TTP259-ASFN datasheet(24/81 Pages) TONTEK

24 / 81 page

Preliminary

TTP259

TonTouch

2015/05/25

Page 24 of 81

Ver: 1.1

S-12. Interrupts

The CPU provides only 1 interrupt vector ($001H) and no priority, but can

expand to multi-sources. Interrupt source includes external interrupts

(INT0,INT1), timer/counter interrupts (TCP1,TCP2), Time base timer interrupt

(TBxINT) or other peripheral device interrupt request (PERINT). The interrupt

control registers (INTC or INTC1) contain the interrupt control bit to enable and

disable corresponding interrupt request and the corresponding interrupt

request flags in the (INTF or INTF1) registers. Before finishing the INT service

routine, another INT request will keep waiting until program return from

interrupt routine.

If the interrupt request needs service, the programmer may set the

corresponding INT enable bit to allow interrupt active. External interrupts are

triggered by both falling and rising edge trigger and set the related interrupt

request flag (INTFx). The internal timer/counter interrupt is setting the TCPxF

to 1, resulting from the timer/counter overflow. The time base interrupt TBxINT

was provided 2 periodic interrupt request cycles for user operating a periodic

routine.

When the corresponding interrupt enable and flag bit is set to 1, the CPU

will active the interrupt service routine. Then CPU reads the service flag and

check the request priority then proceeds with the relative interrupt service.

After CPU writes the corresponding bit to 0 in the INTFx register, the service

flag will be cleared to 0(using STX #n,$m instruction). The INTF and INTF1

registers’ bit can only write 0 to clear the flag. User writes 1 to flag bit with no

effect.

INT0 input type can select Schmitt or comparator by SPCON1 register, if

comparator select then the comparator reference voltage is the bandgap

voltage(1.12+-10%), it will consumption more current than Schmitt because

bandgap turn on. It can be used to detect VDD voltage for battery low and so

on.

TTP259-ASFN Datasheet(PDF) 24 Page - Tontek Design Technology