PXR40RM Datasheet, PDF (1236/1434 Pages) Freescale Semiconductor, Inc – PXR40 Microcontroller

Enhanced Time Processing Unit (eTPU2)
The TCR1 bus runs through all the local engine channels
29.3.5.1.1 Externally Clocked Mode
TCR1 can be driven externally by the TCRCLK input, after the digital filter. The TCR1 clock source is
configured by the TCR1CTL bit, as shown in Figure 29-31. For more information on clock source
selection, please refer to Section 29.2.6.1, ETPUTBCR - eTPU Time Base Configuration Register.
TCRCLK Prescaler
Input Originated
In TCRCLK pin,
00
after the filter
1
System
Clock
0
div 2
10
no clock
11
TCR1CS
TCR1CTL
TCR1
Prescaler
1,2,3,..,256
8
TCR1P
TCR1
Red Line (STAC) bus
Figure 29-31. TCR1 Clock Selection
29.3.5.1.2 Internally Clocked Mode
TCR1 can be driven by the eTPU clock or eTPU clock divided by 2, before the prescaler. TCR1CTL can
also be used to freeze TCR1 clock independently of TCR2 (unlike GTBE).
29.3.5.1.3 TCR1 Clock Prescaling
Any clock source selected by TCR1CTL is prescaled by a factor of 1 to 256, selected by ETPUTBCR field
TCR1P. For more information on prescaler configuration refer to Section 29.2.6.1, ETPUTBCR - eTPU
Time Base Configuration Register. The TCR1 Prescaler resets when etpu_gtbe_in is negated. After reset,
it starts counting up to TCR1P when etpu_gtbe_in is asserted. When TCR1 increments (etpu_gtbe_in=1),
the prescaler starts a new count and the new TCR1P becomes effective. When TCR1 is written by
microcode, the prescaler is reloaded with TCR1P and it becomes effective, if etpu_gtbe_in is asserted.
29.3.5.1.4 STAC Bus Client Mode
In this mode the TCR1 register is continuously updated from the STAC bus, and the clock selection and
prescaling logic becomes ineffective. It is not writable by the microcode, and when read, it reflects the
STAC bus imported value. The use of EAC is not allowed in client mode. This mode is configured through
the register ETPUREDCR (see Section 29.2.6.4, ETPUREDCR - eTPU STAC Configuration Register).
29.3.5.1.5 STAC Bus Server Mode
TCR1 bus can be exported to the STAC bus as a server, providing time information to other peripherals.
This mode is configured through the register ETPUREDCR (see Section 29.2.6.4, ETPUREDCR - eTPU
STAC Configuration Register).
29.3.5.2 Timer Count Register 2 - TCR2
The TCR2 is a 24-bit counter which can be used in the following modes:
29-68
PXR40 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor