EM357-RTR Ember, EM357-RTR Datasheet - Page 149

• Manufacturer Part Number: EM357-RTR
• Description: IC RF TXRX ZIGBEE 192KB 48QFN
• Manufacturer: Ember

Specifications of EM357-RTR

• Frequency: 2.4GHz
• Data Rate - Maximum: 250kbps
• Modulation Or Protocol: 802.15.4 Zigbee
• Applications: General Purpose
• Power - Output: 5dBm
• Sensitivity: -100dBm
• Voltage - Supply: 2.1 V ~ 3.6 V
• Current - Receiving: 26mA
• Current - Transmitting: 31mA
• Data Interface: PCB, Surface Mount
• Memory Size: 192kB Flash, 12kB RAM
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 48-QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 636-1011-2

A rising edge on TI1 enables the counter and sets the INT_TIMTIF flag. The counter then counts on ETR rising
edges. The delay between the rising edge of the ETR signal and the actual reset of the counter is due to the
resynchronization circuit on ETRP input.
9.3.14 Timer Synchronization
The two timers can be linked together internally for timer synchronization or chaining. A timer configured in
master mode can reset, start, stop or clock the counter of the other timer configured in slave mode.
Figure 9-31 presents an overview of the trigger selection and the master mode selection blocks.
9.3.14.1
For example, to configure Timer 1 to act as a prescaler for Timer 2:
Note: If OCy is selected on Timer 1 as trigger output (TIM_MMS = 1xx), its rising edge is used to clock the
counter of Timer 2.
Configure Timer 1 in master mode so that it outputs a periodic trigger signal on each UEV. Writing
TIM_MMS = 010 in the TIM1_CR2 register causes a rising edge to be output on TRGO each time a UEV is
generated.
To connect the TRGO output of Timer 1 to Timer 2, configure Timer 2 in slave mode using ITR0 as an
internal trigger. Write TIM_TS = 100 in the TIM2_SMCR register.
Put the slave mode controller in external clock mode 1: Write TIM_SMS = 111 in the TIM2_SMCR register.
This causes Timer 2 to be clocked by the rising edge of the periodic Timer 1 trigger signal, which
corresponds to the Timer 1 counter overflow.
Finally, enable both timers: Set their respective TIM_CEN bits in the TIMx_CR1 register.
Using One Timer as Prescaler for the Other Timer
Figure 9-30. Control circuit in External Clock Mode 2 + Trigger Mode
Figure 9-31. Master/Slave Timer Example
Final
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120-035X-000G