Ring Section

Ring Configuration Page

In the System Explorer window configuration tree, expand Targets >> Controller >> Custom Devices >> CMDE Add-On and select a Ring section to display this page. Use this page to enable or disable individual cell monitoring devices within a ring.

This page includes the following components, configurable at edit-time only:

Ring
Name	Specifies the name of the ring.
Description	Specifies a description for the ring.
Configuration
Device Type	Specifies the type of cell monitoring device making up the ring.
Target	Specifies the name of the FPGA target on which the ring will be simulated once the project is deployed. This must match the name of the FPGA target as displayed in NI MAX.
Enable All	Enables all cell monitoring devices in the ring.
Disable All	Disables all cell monitoring devices in the ring.
Device	This table allows each cell monitoring device within the ring to be enabled or disabled. A Device section is added to the System Definition tree for each enabled device. See Considerations when Enabling Devices for additional information.

Ring Section Channels

This section includes the following custom device channels. The value of an input channel can be modified dynamically at execution time.

Channel Name	Type	Default Value	Description

Channel Name

Type

Default Value

Description

SPI Mode

Input

0

Specifies the SPI Mode for all devices in the ring. This channel accepts numeric integers 0 through 3, inclusive, as defined below:

0 - SPI Mode 0, where CPOL=0 and CPHA=0
1 - SPI Mode 1, where CPOL=0 and CPHA=1
2 - SPI Mode 2, where CPOL=1 and CPHA=0
3 - SPI Mode 3, where CPOL=1 and CPHA=1

Please refer to the de facto SPI standard for detailed information about SPI mode numbers.

This channel may not be available for all device types. Please refer to the device-specific pages in this document for information about supported SPI Modes.

Known Issue CMDETT-47 may impact the behavior of this channel.

Ring Topology

A ring consists of a group of emulated cell monitoring devices arranged in a daisy-chain configuration. Each device is connected to its neighbor through a bidirectional SPI interface, with the first and last devices mapped to Digital IO channel groups Port A and Port B, respectively. The ring is emulated on the FPGA board specified in the Target indicator.

When a device is disabled, the SPI connection passes through the disabled device and onto the next enabled one. Although a disabled device does not break the connectivity of the ring, it does introduce a small delay in the SPI communication. See Considerations when Enabling Devices for additional information

A 6-device ring with all devices enabled (left), and the same ring with Device 2, Device 4, and Device 5 disabled (right).

Considerations when Enabling Devices

Consider the following recommendations and limitations when choosing which devices to enable within the ring:

The maximum quantity of enabled devices is dependent upon the limitations set by the deployment License.
For each enabled device, additional CPU resources will be required to execute the simulation.
A disabled device introduces a small delay in the SPI communication. As a result, it is not recommended to disable more than five consecutive devices. Consider alternating between enabled and disabled devices in the ring daisy chain if this is a concern.