Datasheet

QuickLogic EOS S3 Ultra Low Power multicore MCU datasheet - Version 3.3d 27-129

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Interface to the On-Chip Programmable Logic

IP within the on-chip programmable logic can use the following interfaces to communicate with resources outside of the

chip. These include:

• EOS S3 Platform

• SPI Master Interface for System Support

• Sensor Processing Subsystem

• Packet FIFO

These resources help the IP to coordinate its activities with other modules in the EOS S3 platform. Additionally, the IP

can call upon external resources to support its processing activities. The following sections describe the resources

available to the IP within the on-chip programmable logic. It is not essential that the IP within the on-chip programmable

logic use these interfaces.

6.3.1. EOS S3 Platform Interface

The interface between IP in the on-chip programmable logic and the EOS S3 platform consists of the following:

• Data transfer interface via an AHB-to-Wishbone bridge

• SDMA interface

• Interrupt interface

6.3.2. AHB-To-Wishbone Bridge

The AHB-To-Wishbone Bridge provides the means for the EOS S3 platform (M4-F or AP) to access IP within the on-chip

programmable logic. Specifically, this interface takes a 32-bit address and data on its AHB port and passes these values

to the Wishbone bus. The following figure illustrates the AHB-to-Wishbone bridge.

Figure 39: AHB-to-Wishbone Bridge

Wishbone Bus

AHB Slave

AHB-to-Wishbone Bridge

EOS System

FPGA Fabric

The connection between the AHB Slave and Wishbone Bus supports asynchronous transfers. This allows the on-chip

programmable logic-based IP to use a clock frequency appropriate to its operation without the EOS S3 platform losing

its ability to communicate with the resources of the IP. For example, most IPs require the use of some type of Start or

Stop register bit to control their operations. The asynchronous interface ensures that the EOS S3 platform can still access

these registers.

It is important to note that the on-chip programmable logic-based IP does not have the ability to initiate direct transfers

to the EOS S3 platform. This is done for two reasons: first, the Wishbone bus cannot support multiple masters (the

Wishbone interface only supports Wishbone clients) and second, the AHB Slave interface cannot master the AHB bus.