PNI SENtral - Manual (Page 18)

PNI Sensor Corporation Doc #1018049 R03
SENtral Technical Data Sheet Page 17
Prior to running SENtral, the Configuration File must be uploaded into SENtral’s Configuration
RAM. This file contains information regarding how the user’s sensor system is configured, such
as sensor models, sensor slave addresses, GPIO pin assignments, etc.. The Configuration File is
generated with the SENtral Configuration Tool, as discussed in Section 6. It may be stored in
the host processor’s non-volatile memory or in a dedicated EEPROM connected to SENtral’s
sensor bus. Once the Configuration File is uploaded, SENtral will move into Initialized state.
Once the initialization sequence is complete, there are three states in which SENtral may reside:
Normal Operation, Standby, and Pass-Through. Figure 5-2 indicates the recommended way to
get from one state to another, and these states are discussed in detail in Sections 225.3 (Normal
Operation), 5.4 (Standby), and 5.5 (Pass-Through).
Figure 5-2: SENtral Operational States
5.1 Power-Up and Configuration File Upload
After powering up or issuing a ResetReq command, SENtral automatically initializes the
registers, and then looks for an EEPROM on the sensor bus, as indicated in Figure 5-1.
The Configuration File must now be uploaded. This file contains information on how the
sensor system is configured in the user’s system, and is generated with the SENtral
Configuration Tool, as discussed in Section 6. It can be stored in non-volatile memory in the
host CPU or in a dedicated EEPROM. The primary advantages of using a dedicated
EEPROM are freeing up host processor memory and minimizing the time from powering up
until the upload is complete. The advantages of using the host CPU’s memory are no
additional cost and no additional system footprint requirement. If a dedicated EEPROM is
used, the EEPROM needs to be connected to SENtral as a slave device on the sensor bus.
5.1.1 Configuration File Upload from EEPROM
If a dedicated EEPROM is used to store the Configuration File, then this EEPROM
initially would be loaded with the Configuration File either using an EEPROM
programmer or by writing the file into the EEPROM from the host while SENtral is in
Pass-Through State. This later method also can be used if a new revision of the SENtral
algorithm is available or if the user is testing a variety of sensors and consequently needs