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Chapter 11 Enhanced Capture Timer (S12MC9S12XDP51216B8CV2)
MC9S12XDP512 Data Sheet, Rev. 2.11
520 Freescale Semiconductor
11.3.2.6 Timer System Control Register 1 (TSCR1)
Read or write: Anytime except PRNT bit is write once
All bits reset to zero.
Module Base + 0x0006
76543210
R
TEN TSWAI TSFRZ TFFCA PRNT
000
W
Reset 00000000
= Unimplemented or Reserved
Figure 11-9. Timer System Control Register 1 (TSCR1)
Table 11-7. TSCR1 Field Descriptions
Field Description
7
TEN
Timer Enable
0 Disables the main timer, including the counter. Can be used for reducing power consumption.
1 Allows the timer to function normally.
Note: If for any reason the timer is not active, there is no ÷64 clock for the pulse accumulator since the ÷64 is
generated by the timer prescaler.
6
TSWAI
Timer Module Stops While in Wait
0 Allows the timer module to continue running during wait.
1 Disables the timer counter, pulse accumulators and modulus down counter when the MCU is in wait mode.
Timer interrupts cannot be used to get the MCU out of wait.
5
TSFRZ
Timer and Modulus Counter Stop While in Freeze Mode
0 Allows the timer and modulus counter to continue running while in freeze mode.
1 Disables the timer and modulus counter whenever the MCU is in freeze mode. This is useful for emulation.
The pulse accumulators do not stop in freeze mode.
4
TFFCA
Timer Fast Flag Clear All
0 Allows the timer flag clearing to function normally.
1 A read from an input capture or a write to the output compare channel registers causes the corresponding
channel flag, CxF, to be cleared in the TFLG1 register. Any access to the TCNT register clears the TOF flag
in the TFLG2 register. Any access to the PACN3 and PACN2 registers clears the PAOVF and PAIF flags in the
PAFLG register. Any access to the PACN1 and PACN0 registers clears the PBOVF flag in the PBFLG register.
Any access to the MCCNT register clears the MCZF flag in the MCFLG register. This has the advantage of
eliminating software overhead in a separate clear sequence. Extra care is required to avoid accidental flag
clearing due to unintended accesses.
Note: The flags cannot be cleared via the normal flag clearing mechanism (writing a one to the flag) when
TFFCA = 1.
3
PRNT
Precision Timer
0 Enables legacy timer. Only bits DLY0 and DLY1 of the DLYCT register are used for the delay selection of the
delay counter. PR0, PR1, and PR2 bits of the TSCR2 register are used for timer counter prescaler selection.
MCPR0 and MCPR1 bits of the MCCTL register are used for modulus down counter prescaler selection.
1 Enables precision timer. All bits in the DLYCT register are used for the delay selection, all bits of the PTPSR
register are used for Precision Timer Prescaler Selection, and all bits of PTMCPSR register are used for the
prescaler Precision Timer Modulus Counter Prescaler selection.