Texas Instruments RM46 Hercules Safety MCU controlCARD TMDXRM46CNCD TMDXRM46CNCD Datenbogen
Produktcode
TMDXRM46CNCD
VCLKA4_SRC
0
1
3
4
5
6
7
1
3
4
5
6
7
VCLK
VCLKA4_S (left open)
/DIVR
PLL2 post_ODCLK/8
PLL2 post_ODCLK/16
VCLKA4_DIVR_EMAC
(to EMAC)
(to EMAC)
SPNS184A – SEPTEMBER 2012 – REVISED SEPTEMBER 2013
4.6.2.3
Special Clock Source Selection Scheme for VCLKA4_DIVR_EMAC
Some applications may need to use both the of Ethernet interfaces. The MII interface requires
VCLKA4_DIVR_EMAC to be 25MHz and the RMII requires VCLKA4_DIVR_EAMC to be 50MHz.
VCLKA4_DIVR_EMAC to be 25MHz and the RMII requires VCLKA4_DIVR_EAMC to be 50MHz.
These different frequencies are supported by adding special dedicated clock source selection options for
the VCLKA4_DIVR_EMAC clock domain. This logic is shown in .
the VCLKA4_DIVR_EMAC clock domain. This logic is shown in .
Figure 4-8. VCLKA4_DIVR Source Selection Options
The PLL2 post_ODCLK is brought out as a separate output from the PLL wrapper module. There are two
additional dividers implemented at the device-level to divide this PLL2 post_ODCLK by 8 and by 16.
additional dividers implemented at the device-level to divide this PLL2 post_ODCLK by 8 and by 16.
As shown in , the VCLKA4_SRC configured via the system module VCLKACON1 control register is used
to determine the clock source for the VCLKA4_S and VCLKA4_DIVR. An additional multiplexor is
implemented to select between the VCLKA4_DIVR and the two additional clock sources – PLL2
post_ODCLK/8 and post_ODCLK/16.
to determine the clock source for the VCLKA4_S and VCLKA4_DIVR. An additional multiplexor is
implemented to select between the VCLKA4_DIVR and the two additional clock sources – PLL2
post_ODCLK/8 and post_ODCLK/16.
The selection is done as shown in the following table.
Table 4-14. VCLKA4_DIVR_EMAC Clock Source
Selection
VCLKA4_SRC from
Clock Source for
VCLKACON1[19–16]
VCLKA4_DIVR_EMAC
0x0
OSCIN / VCLKA4R
0x1
PLL1CLK / VCLKA4R
0x2
Reserved
0x3
EXTCLKIN1 / VCLKA4R
0x4
LF LPO / VCLKA4R
0x5
HF LPO / VCLKA4R
0x6
PLL2CLK / VCLKA4R
0x7
EXTCLKIN2 / VCLKA4R
72
System Information and Electrical Specifications
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