EM357-RTR Ember, EM357-RTR Datasheet - Page 135

• 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

Figure 9-15 gives an overview of the external trigger input block.
For example, to configure the up-counter to count each 2 rising edges on ETR, use the following procedure:
The counter counts once each 2 ETR rising edges. The delay between the rising edge on ETR and the actual
clock of the counter is due to the resynchronization circuit on the ETRP signal.
Figure 9-16 illustrates counting every 2 rising edges of ETR using external clock mode 2.
TIM_EXTRIGSEL bits Clock Signal Selection
As no filter is needed in this example, write TIM_ETF = 0000 in the TIMx_SMCR register.
Set the prescaler: Write TIM_ETPS = 01 in the TIMx_SMCR register.
Select rising edge detection on ETR: WriteTIM_ETP = 0 in the TIMx_SMCR register.
Enable external clock mode 2: Write TIM_ECE = 1 in the TIMx_SMCR register.
Enable the counter: Write TIM_CEN = 1 in the TIMx_CR1 register.
00
01
10
11
PCLK (peripheral clock). When running from the 24 MHz crystal oscillator, the PCLK
TIMxCLK pin. If the TIM_CLKMSKEN bit in the TIMx_OR register is set, this signal is
frequency is 12 MHz. When the 12 MHz RC oscillator is in use, the frequency is 6 MHz.
Calibrated 1 kHz internal RC oscillator
Optional 32.786 kHz clock
AND’ed with the TIMxMSK pin providing a gated clock input.
Table 9-2. TIM_EXTRIGSEL Clock Signal Selection
Figure 9-15. External Trigger Input Block
Final
9-11
EM351 / EM357
120-035X-000G