JN5148/001,518 NXP Semiconductors, JN5148/001,518 Datasheet - Page 22

• Manufacturer Part Number: JN5148/001,518
• Description: MCU 802.15.4 32BIT 2.4G 56-QFN
• Manufacturer: NXP Semiconductors
• Series: JN5148r

Specifications of JN5148/001,518

• Frequency: 2.4GHz
• Data Rate - Maximum: 667kbps
• Modulation Or Protocol: 802.15.4
• Applications: Home/Building Automation, Industrial Control
• Power - Output: 2.5dBm
• Sensitivity: -95dBm
• Voltage - Supply: 2 V ~ 3.6 V
• Current - Receiving: 17.5mA
• Current - Transmitting: 15mA
• Data Interface: PCB, Surface Mount
• Memory Size: 128kB RAM, 128kB ROM
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 56-VFQFN
• Core: RISC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The external resistor and capacitor provide a simple reset operation when connected to the RESETN pin.
6.2 External Reset
An external reset is generated by a low level on the RESETN pin. Reset pulses longer than the minimum pulse width
will generate a reset during active or sleep modes. Shorter pulses are not guaranteed to generate a reset. The
JN5148 is held in reset while the RESETN pin is low. When the applied signal reaches the Reset Threshold Voltage
(V
Multiple devices may connect to the RESETN pin in an open-collector mode. The JN5148 has an internal pull-up
resistor connect to the RESETN pin. The pin is an input for an external reset, an output during the power-on reset
and may optionally be an output during a software reset. No devices should drive the RESETN pin high.
6.3 Software Reset
A system reset can be triggered at any time through software control, causing a full chip reset and invalidating the
RAM contents. For example this can be executed within a user’s application upon detection of a system failure. When
performing the reset, the RESETN pin is driven low for 1µsec; depending on the external components this may or
may not be visible on the pin.
In addition, the RESETN line can be driven low by the JN5148 to provide a reset to other devices in the system (e.g.
external sensors) without resetting itself. When the RESETN line is not driven it will pull back high through either the
internal pull-up resistor or any external circuitry. It is essential to ensure that the RESETN line pulls back high within
100µsec after the JN5148 stops driving the line; otherwise a system reset will occur. Due to this, careful consideration
should be taken of any capacitance on this line. For instance, the RC values recommended in section 6.1 may need
to be replaced with a suitable reset IC
22
RST
) on its positive edge, the internal reset process starts.
RESETN pin
R1
C1
Figure 12: External Reset Generation
VDD
Figure 13: External Reset
JN-DS-JN5148-001 1v6
18k
470nF
Reset
JN5148
RESETN
Internal Reset
© NXP Laboratories UK 2010