SH79F166APSLASH044PR datasheet(50/113 Pages) SINOWEALTH

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SH79F166A

7.8.5 Timer5

Timer5 is a 16-bit auto-reload timer. It is accessed as two cascaded data registers: TH5 and TL5. It is controlled by the T5CON

When writing to TH5 and TL5, they are used as timer load register. When reading from TH5 and TL5, they are used as timer

counter register. Setting the TR5 bit enables Timer5 to count up. The timer will overflow from 0xFFFF to 0x0000 and set the TF5

bit. This overflow also causes the 16-bit value written in timer load register to be reloaded into the timer counter register. Writing

to TH4 also can cause the 16-bit value written in timer load register to be reloaded into the timer counter register.

Read or write operation to TH5 and TL5 should follow these steps:

Write operation:Low nibble first,High nibble to update the counter.

Read operation:High nibble first,Low nibble followed.

Timer5 Modes

Timer5 has one operating modes: 16-bit auto-reload counter/timer.

Mode0: 16 bit Auto-Reload Counter/Timer

Timer5 operates as 16-bit counter/timer in Mode 0. The TH5 register holds the high eight bits of the 16-bit counter/timer, TL5

holds the low eight bits. As the 16-bit timer register increments and overflows from 0xFFFF to 0x0000, the timer overflow flag

TF5 (T5CON.7) is set and the 16-bit value in timer load register are reloaded into timer counter register, and an interrupt will

occur if Timer 5 interrupts is enabled. The T4CLKS bit (T4CON.0) selects the counter/timer's clock source.

Setting the TR5 bit (T5CON.1) enables the timer. Setting TR5 does not force the timer to reset. The timer load register should

be loaded with the desired initial value before the timer is enabled.

TF5

The Block Diagram of Mode 0 of Timer 5

TL5

TH5

Increment Mode

0:Switch Off

1:Switch On

16 bit Counter

Interrupt

Request

Overflow

Flag

TR5

System Clock

Prescaler

1,8,64,256

T5PS[1:0]

SH79F166AP/044PR Datasheet(PDF) 50 Page - SINOWEALTH Electronic Ltd