收藏本站
MRF49XA
3.16 Sleep, Wake-up and Battery
Operations
The advanced interrupt handler circuit is configured in
the transmitter to reduce the power consumption. As
mentioned, the Sleep mode is the lowest power
consumption mode in which the clock and all functional
blocks of the device are disabled. In case of any
interrupt, the device wakes up, switches to Active mode
and an interrupt signal generated on the IRO pin
indicates the change in state to the host
microcontroller. The source of the interrupt can be
determined by reading the status word of the device
(see Register 2-1 ).
To reduce current consumption, the MRF49XA should
be placed in the low-power consuming Sleep mode. In
Sleep mode, the 10 MHz main oscillator is turned off,
disabling the RF and baseband circuitry. Data is
retained in the control and FIFO registers and the
transceiver is accessible through the SPI port.
The MRF49XA will not enter Sleep mode if any of the
interrupt remains active, irrespective of the state of the
OSCEN bit in the PMCREG. This way, the
microcontroller can always have a clock signal to
process the interrupt. To prevent high-current
consumption, which results in shorter battery life, it is
highly recommended to process and clear interrupts
before entering Sleep mode. The functions which are
not necessary should be turned off to avoid unwanted
interrupts.
To minimize the current consumption, the MRF49XA
supports different power-saving modes, along with an
integrated wake-up timer. Active mode can be
reinitiated by the following ways:
? By applying the wake-up events’ negative logical
pulse on INT pin
? Wake-up timer time-out
? Low supply voltage detection
? On-chip FIFO filled up
The device has the ability to wake itself up from Sleep
mode through a wake-up timer. The WTSREG sets the
wake-up interval for the MRF49XA. After setting the
wake-up interval, the WUTEN bit (PMCREG<1>)
should be cleared and set at the end of every wake-up
cycle.
The Wake-up Duration Time (WUTIME) is calculated
as shown in Equation 3-4 .
EQUATION 3-4:
WUTIME = 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
Note: WUTIME is measured in ms.
The Battery Threshold Detect feature is useful in
monitoring the discharge-sensitive batteries, such as
Lithium cells. The LBDEN bit (PMCREG<2>) is used to
enable or disable the low battery detect feature.
The BCSREG configures the following:
? Output clock frequency
? Low battery detect threshold
The low battery threshold value is programmable from
2.2V to 3.8V and is calculated by using Equation 3-5 .
EQUATION 3-5:
Threshold Voltage Value = 2.25 + 0.1 x (LBDVB<3:0>)
where:
LBDVB<3:0> is the Decimal Value from 0-15
When the battery level falls 50 mV below this value, the
LBTD bit (STSREG<10>) is set, indicating that the
battery level is below the programmed threshold.
The registers associated with power-saving modes
are:
? On receiving a request through the serial interface
To make the MRF49XA device enter into Sleep mode,
certain control register values must be initialized. The
sequence to program the control registers for entering
into Sleep and Wake-up modes is as follows:
For Sleep mode:
?
?
?
?
?
?
STSREG (see Register 2-1 )
GENCREG (see Register 2-2 )
TXCREG (see Register 2-4 )
RXCREG (see Register 2-7 )
PMCREG (see Register 2-13 )
WTSREG (see Register 2-14 )
1.
2.
3.
4.
Check the IRO bit status
Read STSREG
Configure GENCREG
Configure PMCREG for oscillator and clock
?
BCSREG (see Register 2-16 )
buffering
For Wake-up mode:
1.
2.
3.
Enter in TX/RX mode or
Enable crystal or
Set the INT pin
? 2009-2011 Microchip Technology Inc.
Preliminary
DS70590C-page 65
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
MRF89XA-I/MQ TXRX ISM SUB-GHZ ULP 32QFN
MRF89XAM9A-I/RM IC TXRX MOD 915MHZ ULP SUB-GHZ
MRX-001-433DR-B MODULE RECEIVER 433MHZ 18DIP
MRX-002-433DR-B MODULE RECEIVER 433MHZ 18DIP
MRX-002SL-433DR-B MODULE RCVR 433MHZ SAW LN 24DIP
MRX-005-915DR-B MODULE RECEIVER 915MHZ 18DIP
MRX-005SL-915DR-B MODULE RCVR 915MHZ SAW LN 24DIP
MRX-007-433DR-B MODULE RECEIVER 433MHZ 18DIP
相关代理商/技术参数
MRF49XAT-I/T 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:ISM Band Sub-GHz RF Transceiver
MRF49XAT-I-ST 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:ISM Band Sub-GHz RF Transceiver
MRF49XAT-I-T 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:ISM Band Sub-GHz RF Transceiver
MRF4A(AMMO) 制造商:Bel Fuse 功能描述:FUSE
MRF5 制造商:Ferraz Shawmut 功能描述:
MRF50 制造商:Ferraz Shawmut 功能描述:
MRF500 制造商:Ferraz Shawmut 功能描述:
MRF5003 制造商:MOTOROLA 制造商全称:Motorola, Inc 功能描述:N-CHANNEL BROADBAND RF POWER FET