Timer 3 control/mode register (t3cm) – Maxim Integrated High-Speed Microcontroller Users Guide: Network Microcontroller Supplement User Manual

Page 93

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High-Speed Microcontroller User’s

Guide: Network Microcontroller

Supplement

93

7

6

5

4

3

2

1

0

SFR FDh

TF3

TR3

T3M

SMOD_2

GATE

C/T3

M1

M0

RW-0

RW-0

RW-0

RW-0

RW-0

RW-0

RW-0

RW-0

Timer 3 Control/Mode Register (T3CM)

R = Unrestricted read, W = Unrestricted write, -n = Value after reset

TF3
Bit 7

TR3
Bit 6

T3M
Bit 5

SMOD_2
Bit 4

GATE
Bit 3

C/T3
Bit 2

M1-0
Bits 1-0

Timer 3 overflow flag. This bit is set to 1 when timer 3 overflows its maximum count, as defined by the
current mode. It is cleared either by software or by the start of the timer 3 interrupt service routine. A

zero on this bit indicates that no timer 3 overflow has been detected.

Timer 3 run control. Setting this bit enables timer 3. Clearing this bit halts timer 3.

Timer 3 clock select. This bit controls the division of the system clock that drives timer 3. This bit has
no effect on instruction cycle timing.

0 = Timer 3 uses a divide-by-12 of the crystal frequency.

1 = Timer 3 uses a divide-by-4 of the system clock frequency.

Serial port 2 baud-rate doubler enable. Setting this bit enables the serial baud-rate doubling function
in mode 1, 2, and 3 for serial port 2. A 0 disables the doubler.

Timer 3 gate control.

GATE = 0: Timer 3 clocks when TR3 is 1, regardless of INT3.

GATE = 1: Timer 3 clocks only when TR1 and INT3 are 1.

Counter/timer 1 select.

C/T3 = 0: Selects timer function with internal clock for timer 3.

C/T3 = 1: Selects counter function with input from T3 when TR3 is 1.

Timer 3 mode-select bits 1 and 0.

M1

M0

TIMER MODE

0

0

Mode 0: 8-bit with 5-bit prescale

0

1

Mode 1: 16-bit with no prescale

1

0

Mode 2: 8-bit with autoreload

1

1

Mode 3: Timer 3 is halted, but its count is held.

Maxim Integrated

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