Hello Hobie Cat,
Osctune is where you tweak the OSC,
from the data sheet below:
OCSTUNE = 0' runs at calibrated freq.
OSCTUNE = %00001111 ' OSC TWEAKED TO FREQ + x percent
OSCTUNE = %00010000 ' OSC tweaked to FREQ - x percent


Code:
REGISTER 3-2: OSCTUNE: OSCILLATOR TUNING REGISTER
U-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
— — — TUN4 TUN3 TUN2 TUN1 TUN0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-5 Unimplemented: Read as ‘0’
bit 4-0 TUN<4:0>: Frequency Tuning bits
01111 = Maximum frequency
01110 =
•
•
•
00001 =
00000 = Oscillator module is running at the calibrated frequency.
11111 =
•
•
•
10000 = Minimum frequency