Datasheet

56F8037/56F8027 Data Sheet, Rev. 8
102 Freescale Semiconductor
6.3.8 Peripheral Clock Rate Register (SIM_PCR)
By default, all peripherals are clocked at the system clock rate, which has a maximum of 32MHz. Selected
peripherals clocks have the option to be clocked at 3X system clock rate, which has a maximum of 96MHz,
if the PLL output clock is selected as the system clock. If PLL is disabled, the 3X system clock will not be
available. This register is used to enable high-speed clocking for those peripherals that support it.
Note: Operation is unpredictable if peripheral clocks are reconfigured at runtime, so peripherals should be
disabled before a peripheral clock is reconfigured.
Figure 6-9 Peripheral Clock Rate Register (SIM_PCR)
6.3.8.1 Quad Timer B Clock Rate (TMRB_CR)—Bit 15
This bit selects the clock speed for the Quad Timer B module.
• 0 = Quad Timer B clock rate equals the system clock rate, to a maximum 32MHz (default)
• 1 = Quad Timer B clock rate equals 3X system clock rate, to a maximum 96MHz
6.3.8.2 Quad Timer A Clock Rate (TMRA_CR)—Bit 14
This bit selects the clock speed for the Quad Timer A module.
• 0 = Quad Timer A clock rate equals the system clock rate, to a maximum 32MHz (default)
• 1 = Quad Timer A clock rate equals 3X system clock rate, to a maximum 96MHz
6.3.8.3 Pulse Width Modulator Clock Rate (PWM_CR)—Bit 13
This bit selects the clock speed for the PWM module.
• 0 = PWM module clock rate equals the system clock rate, to a maximum 32MHz (default)
• 1 = PWM module clock rate equals 3X system clock rate, to a maximum 96MHz
6.3.8.4 Inter-Integrated Circuit Run Clock Rate (I2C_CR)—Bit 12
This bit selects the clock speed for the I
2
C run clock.
•0 = I
2
C module run clock rate equals the system clock rate, to a maximum 32MHz (default)
•1 = I
2
C module run clock rate equals 3X system clock rate, to a maximum 96MHz
6.3.8.5 Reserved—Bits 11–0
This bit field is reserved. Each bit must be set to 0.
Base + $B
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Read
TMRB_
CR
TMRA_
CR
PWM_
CR
I2C_
CR
0 0 0 0 0 0 0 0 0 0 0 0
Write
RESET
0 0 0000 0 0 00000000