I've been experimenting with the nRF5340's HFCLKAUDIO clock, and have discovered a discrepancy that I cannot reconcile.
Table 23 in the datasheet details the peripheral's frequency ranges, along with the Min/Center/Max register values required to create a given clock output.
But according to the equation provided in Figure 20 which dictates the relationship between register value and output frequency, the center value of 39854 (0x9BAE) does NOT result in a 12,288,000Hz clock, rather it produces 12,288,300Hz.
Even accounting for a minimum resolution of 40.7Hz, this seems markedly inaccurate. By my calculations, the closest frequency attainable is 12,288,004Hz which requires a register value of 39846 (0x9BA6).
reg_value 39854 = f_out 12,288,300.08
reg_value 39846 = f_out 12,288,004.56
I understand that clock circuits and locked loops are designed to accommodate slight timing variances, but can anyone from Nordic explain this apparent lack of precision in the datasheet? Is it a typo, or is there some other hidden aspect of the setting that I'm simply unaware of?
Any additional info appreciated.
