The series 400 comes equipped with one-time programmable memory making it suitable for cost sensitive designs where reprogramming is not required. The vast majority of applications use the Series 300 chip and its Flash-based memory. The re-programmable Flash memory is better suited to development programs and applications that require updates from time to time.
Sigma Designs has announced the next generation chip called Series 500 to be available in 2013. This chip series will be pin and function interchangeable with the Series 400 but will replace the Series 400 OTP with Flash memory.
Figure 2 and 3
show the most commonly used module ZW3102 from Sigma Designs that combines the Series 300 chip with some capacities, a crystal and an antenna filter.
The antenna filter is needed to comply with the regulations of the license-free frequency bands used for Z-Wave. These antenna filters are frequency-specific for e.g. 868.4 MHz (Europe, Africa and parts of Asia) or 908.4 MHz (North America) and turn the modules into a region specific device. As a result, different hardware exists for different frequency bands, and manufacturers have to manufacture separate hardware e.g. for the European or the US market. The modules can be ordered either directly from the manufacturers or from DigiKey, Sigma Designs' worldwide distributor. The price point depends on volumes but a budgetary estimate of $5 to $6 can be assumed for small production volumes of few thousand modules.
Figure 3: Series 300 Z-Wave module size comparison
The module fans out all I/Os of the SoC. These I/Os are multi-purpose I/Os and can be freely programmed as output, input with or without internal pull up. Certain I/Os have special functions to support commonly-used circuits such as dimmers or motor control.
I/Os for the Series 300 are
• 10 * General Purpose
• Two Interrupt Inputs
• Serial UART
• SPI Interface
• Triac Control, allows directly attaching the Zero Crossing signal of a phase edge dimmer circuit and deliver the Triac control signal to design a dimmer with minimum external components.
• PWM Output
• Four multiplexed 12/8 bit ADC inputs
Generally, the flexible I/O concept and the module approach allow designing products with minimal additional cost. Assuming a project for a simple binary sensor powered by a battery the whole product can be designed with as few as 10 additional components including the external antenna.
The modules provide a SPI interface that is used to program the memory and can be used to attach an external serial SPI EEPROM. The external EEPROM can be used to store additional application data. It is not possible to use the external EEPROM for operation code.
More information about the electrical characteristics of the Z-Wave Module Series 300 can be found in the product specification [Sigma300]. The 8051 compatible microcontroller with internal ROM typically contains and executes the application code of the device. Devices with more complex functions such as remote controls - may use the Z-Wave chip as a companion chip for communication only but the amount of memory and computing power typically allows implementing all needed functions right into the transceiver chip itself to save cost and PCBA foot print.
Figure 4: Z-Wave Communication Stack