DSPIC30F4012 Microchip Technology Inc., DSPIC30F4012 Datasheet - Page 66

• Manufacturer Part Number: DSPIC30F4012
• Description: Dspic30f4011/4012 Enhanced Flash 16-bit Digital Signal Controller
• Manufacturer: Microchip Technology Inc.

dsPIC30F4011/4012
FIGURE 9-1:
9.1
The 16-bit timer can be placed in the Gated Time Accu-
mulation mode. This mode allows the internal T
increment the respective timer when the gate input
signal (T1CK pin) is asserted high. Control bit, TGATE
(T1CON<6>), must be set to enable this mode. The
timer must be enabled (TON = 1) and the timer clock
source set to internal (TCS = 0).
When the CPU goes into the Idle mode, the timer will
stop incrementing unless TSIDL = 0. If TSIDL = 1, the
timer will resume the incrementing sequence upon
termination of the CPU Idle mode.
9.2
The input clock (F
Timer has a prescale option of 1:1, 1:8, 1:64 and 1:256
selected by control bits, TCKPS<1:0> (T1CON<5:4>).
The prescaler counter is cleared when any of the
following occurs:
• a write to the TMR1 register
• clearing of the TON bit (T1CON<15>)
• device Reset, such as POR and BOR
However, if the timer is disabled (TON = 0), then the
timer prescaler cannot be reset since the prescaler
clock is halted.
TMR1 is not cleared when T1CON is written. It is
cleared by writing to the TMR1 register.
DS70135E-page 64
Timer Gate Operation
Timer Prescaler
SOSCO/
SOSCI
T1IF
Event Flag
T1CK
OSC
/4 or external clock) to the 16-bit
16-BIT TIMER1 MODULE BLOCK DIAGRAM (TYPE A TIMER)
TGATE
0
1
Reset
Equal
LPOSCEN
Comparator x 16
TMR1
PR1
CY
to
Q
Q
Gate
Sync
CK
T
D
CY
9.3
During CPU Sleep mode, the timer will operate if:
• The timer module is enabled (TON = 1) and
• The timer clock source is selected as external
• The TSYNC bit (T1CON<2>) is asserted to a logic
When all three conditions are true, the timer will
continue to count up to the Period register and be reset
to 0x0000.
When a match between the timer and the Period regis-
ter occurs, an interrupt can be generated if the
respective timer interrupt enable bit is asserted.
TGATE
(TCS = 1) and
‘0’, which defines the external clock source as
asynchronous
Timer Operation During Sleep
Mode
1 x
0 1
0 0
TON
TSYNC
1
0
© 2007 Microchip Technology Inc.
1, 8, 64, 256
TCKPS<1:0>
Prescaler
Sync
2