6.5.3 Main PLL Control Register
The Main PLL uses two chip-level registers (MAINPLLCTL0 and MAINPLLCTL1) and the PLL controller for its configuration. These MMRs exist inside the Bootcfg space. To write to these registers, software should go through an unlocking sequence using KICK0/KICK1 registers. For valid configurable values into the MAINPLLCTL0 and MAINPLLCTL1 Registers, see Section 6.24. See Section 8.3.4 for the address location of the registers and locking and unlocking sequences for accessing the registers. The registers are reset on POR only. MAINPLLCTL0 is shown in Figure 6-13 and described in Table 6-19. MAINPLLCTL1 is shown in Figure 6-14 and described in Table 6-20.
Figure 6-13 Main PLL Control Register 0 (MAINPLLCTL0)
31 |
|
|
24 |
23 |
|
|
19 |
18 |
|
|
12 |
11 |
6 |
5 |
0 |
BWADJ[7:0] |
Reserved |
PLLM[12:6] |
Reserved |
PLLD |
RW-0000 0101 |
RW-0000 0 |
RW-0000000 |
RW-000000 |
RW-000000 |
Legend: RW = Read/Write; -n = value after reset |
Table 6-19 Main PLL Control Register 0 (MAINPLLCTL0) Field Descriptions
BIT |
FIELD |
DESCRIPTION |
31-24 |
BWADJ[7:0] |
BWADJ[11:8] and BWADJ[7:0] are located in separate registers. The combination (BWADJ[11:0]) should be programmed to a value related to PLLM[12:0] value based on the equation: BWADJ = ((PLLM+1)>>1) -1 |
23-19 |
Reserved |
Reserved |
18-12 |
PLLM[12:6] |
A 13-bit bus that selects the values for the multiplication factor (see the following Note) |
11-6 |
Reserved |
Reserved |
5-0 |
PLLD |
A 6-bit bus that selects the values for the reference divider |
Figure 6-14 Main PLL Control Register 1 (MAINPLLCTL1)
Reserved |
ENSAT |
Reserved |
BWADJ[11:8] |
RW-0000000000000000000000000 |
RW-0 |
RW-00 |
RW-0000 |
Legend: RW = Read/Write; -n = value after reset |
Table 6-20 Main PLL Control Register 1 (MAINPLLCTL1) Field Descriptions
BIT |
FIELD |
DESCRIPTION |
31-7 |
Reserved |
Reserved |
6 |
ENSAT |
Needs to be set to 1 for proper operation of PLL |
5-4 |
Reserved |
Reserved |
3-0 |
BWADJ[11:8] |
BWADJ[11:8] and BWADJ[7:0] are located in separate registers. The combination (BWADJ[11:0]) should be programmed to a value related to PLLM[12:0] value based on the equation: BWADJ = ((PLLM+1)>>1) -1 |
NOTE
PLLM[5:0] bits of the multiplier are controlled by the PLLM Register inside the PLL controller and PLLM[12:6] bits are controlled by the MAINPLLCTL0 chip-level register. The MAINPLLCTL0 Register PLLM[12:6] bits should be written just before writing to the PLLM Register PLLM[5:0] bits in the controller to have the complete 13-bit value latched when the GO operation is initiated in the PLL controller. See the Phase-Locked Loop (PLL) for KeyStone Devices User's Guide for the recommended programming sequence. Output divide ratio and bypass enable/disable of the Main PLL is controlled by the SECCTL Register in the PLL Controller. See the Section 6.5.2.1 for more details.