EM260-BBRD-128K-USART-R Ember, EM260-BBRD-128K-USART-R Datasheet - Page 21

• Manufacturer Part Number: EM260-BBRD-128K-USART-R
• Description: EM260 BREAKOUT BOARD
• Manufacturer: Ember
• Type: Transceiver, 802.15.4/ZigBeer

Specifications of EM260-BBRD-128K-USART-R

• Frequency: 2.4GHz
• For Use With/related Products: EM260
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 636-1026

4.13 Watchdog Timer
4.14 Sleep Timer
4.15 Power Management
register. The value contained in this register could be used to seed a software-generated random number. The
EmberZNet stack utilizes these random numbers to seed the Random MAC Backoff and Encryption Key
Generators.
The EM260 contains an internal watchdog timer clocked from the internal oscillator. If the timer reaches its
time-out value of approximately 2 seconds, it will reset the EM260. This reset signal cannot be routed
externally to the Host.
The EM260 firmware will periodically restart the watchdog timer while the firmware is running normally. The
Host cannot effect or configure the watchdog timer.
The 16-bit sleep timer is contained in the always-powered digital block. The clock source for the sleep timer
is a calibrated 1kHz clock. The frequency is slowed down with a 2
resolution of 1ms. With a 1ms tick and a 16-bit timer, the timer wraps about every 65.5 seconds. The
EmberZNet stack appropriately handles timer wraps allowing the Host to order a theoretical maximum sleep
delay of 4 million seconds.
The EM260 supports four different power modes: active, idle, deep sleep, and power down.
Active mode is the normal, operating state of the EM260.
While in idle mode, code execution halts until any interrupt occurs. All modules of the EM260 including the
radio continue to operate normally. The EmberZNet stack automatically invokes idle as appropriate.
Deep sleep mode and power down mode both power off most of the EM260, including the radio, and leave only
the critical chip functions powered. The internal regulator is disabled and VREG_OUT is turned off. All output
signals are maintained in a frozen state. Upon waking from deep sleep or power down mode, the internal
regulator is re-enabled. Deep sleep and power down result in the same sleep current consumption. The two
sleep modes differ as follows: the EM260 can wake on both an internal timer and an external signal from deep
sleep mode; power down mode can only wake on an external signal.
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prescaler to generate a final timer
EM260
120-0260-000J