Datasheet

MRF49XA
DS70590C-page 38 Preliminary © 2009-2011 Microchip Technology Inc.
EQUATION 2-7:
REGISTER 2-14: WTSREG: WAKE-UP TIMER VALUE SET REGISTER (POR: 0xE196)
W-1 W-1 W-1 W-0 W-0 W-0 W-0 W-1
CCB<15:13> WTEV<4:0>
bit 15 bit 8
W-1 W-0 W-0 W-1 W-0 W-1 W-1 W-0
WTMV<7:0>
bit 7 bit 0
Legend: r = reserved bit
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 15-13 CCB<15:13>: Command Code bits
The command code bits (111b) are serially sent to the microcontroller to identify the bits to be written
in the WTSREG.
bit 12-8 WTEV<4:0>: Wake-up Timer Exponential Value bits
These bits define the exponential value to be used to set up the time interval. The value must be a
decimal equivalent between 0 and 29
(1)
.
bit 7-0 WTMV<7:0>: Wake-up Timer Multiplier Exponential Value bits
These bits define the multiplier value to be used to set up the time interval. The value must be a
decimal equivalent between 0 and 255
(1)
.
Note 1: The WTSREG sets the wake-up interval for the device. After setting the wake-up time, the WUTEN bit
(PMCREG<1>) must be cleared and set at the end of every wake-up cycle. The wake-up duration can be
calculated using Equation 2-7.
WUTIME (ms) =[1.03 x WTMV<7:0> x 2
WTEV<4:0>
] + 0.5 ms
where:
WTMV<7:0> = Decimal Value between 0 to 255
WTEV<4:0> = Decimal Value between 0 to 29