Inter-Processor Interface - Honeywell ISA100 Gen X User Manual

This allows a minimal number of instructs cycles for processing these frequent interrupts and
save significant power.
Chip Select Interrupt
Chip Select interrupt is generated by the Radio to indicate that the data is ready to be sent to the
Sensor Board, or the Radio Board is ready to receive the data sent by the Sensor. The Sensor
acknowledges this interrupt by turning on the SPI receive interrupt. When the data transfer is
complete, the Chip Select line returns to its inactive state.

5.2 Inter-Processor Interface

The Sensor – Radio communication is achieved using a serial peripheral interface (SPI). Two
types of inter processor communication are supported:
1. Network Packets - Packets that have to be transmitted from the Sensor to the
network.
2. Local Packets - Packets exchanged between the Radio and the Sensor.
The SPI IPC interface is designed efficiently to transport packets between the application sub
layer for the Sensor application process and the application sub layer queue implemented on the
Radio. Due to the ASL queue being located on the Radio board, the Sensor sends the request
APDUs to the Radio. The Radio then sends the indication APDUs to the Sensor.
The Sensor board can send packets to the objects on the Radio as local requests packets. Local
request packets are identified by the contract id 0. The Sensor board uses the general read of
attributes from the Radio to retrieve information that is available as attributes in the DMO.
The provisioning devices also use local data packets.
Contracts requests and other stack management functions are implemented as stack specific function calls
that are implemented as a secondary protocol on the Sensor – Radio inter-processor communications. These stack
management functions are provided for the use of a packet class header byte that directs the packet to stack
management access interface.
Release Independent
April 2018
ISA100 Gen X Radio Module User's Guide
Honeywell
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