ZHCSF47E June 2016 – December 2017 TAS2560
PRODUCTION DATA.
The TAS2560 on-chip PLL generates the necessary internal clock frequency for the audio DAC, I-V sensing ADCs, and DSP. The programmability of the PLL allows TAS2560 operation from a wide variety of clocks that may be available in the system application. The configurable PLL clock path is shown in Figure 30.
Figure 30. PLL_CLK Source and Generation
The PLL input supports clocks varying from 512 kHz to 20 MHz and is register programmable to enable generation of required PLL_CLK from various clocks with fine resolution. The PLL output clock PLL_CLK is determined from PLL_CLKIN using the following formula:
The PLL multipliers and dividers are program using the register in Table 2. The table includes also the range of values support and the default values. The D-divider value is 14-bits wide and is controlled by 2 registers. For proper update of the D-divider value, PLL_DVAL_1 must be programmed first followed immediately by PLL_DVAL_2. Unless the write to PLL_DVAL_2 is completed, the new value of D will not take effect.
| PLL Divider | Register Name | Field | Range | Default |
|---|---|---|---|---|
| J | PLL_JVAL[6:0] | PLL_MULT_J | 1, 2, 3, … 63 | 4 |
| D | PLL_DVAL_1[5:0] & PLL_DVAL_2[7:0] | PLL_MULT_D | 0, 1, 2, ... 9999 | 0 |
| P | PLL_CLKIN[5:0] | PLL_P_DIV | 64,1,2,3, ... 63 | 1 |
Field PLL_CLK_SRC in register PLL_CLKIN configures the PLL clock input, PLL_CLKIN.
| PLL_CLKIN[7:6] (PLL_CLK_SRC) | PLL_CLKIN Source |
|---|---|
| 00 | Input from BCLK |
| 01 | Input from MCLK (default) |
| 10 | Input from PDMLK |
| 11 | Reserved |
The following conditions must be satisfied in the PLL configuration:
Finally, the PLL_LOWF field in register PLL_JVAL must be configured properly based on the PLL_INPUT_CLK intermediate clock frequency.
| PLL_JVAL[7] (PLL_LOWF) | PLL_INPUT_CLK Condition |
|---|---|
| 0 | >= 1MHz (default) |
| 1 | < 1MHz |