HyperFlash vs HyperRAM support

[Anonymous]

The HyperBis Chipset support table at http://www.cypress.com/hyperbus-chipset-support  lists some vendor's part such as the K28 as only supporting HyperFlash, but not HyperRAM.  What typically does a host need to do to support both the end devices.  Why would only one device type be supported?  Do you have any better info on K28 Hyperbus support?

[TakahiroK_16 · Accepted solution]

Hello,

The major differences between HyperFlash and HyperRAM are:

1. RWDS signal usage

The HyperFlash uses it only as a read data strobe (output from Flash), while the HyperRAM uses it also as a refresh latency indicator and a write data mask (bidirectional).

2. Address Space (CA Bit 46, Table3.2 in the HyperBus specification, http://www.cypress.com/file/213356/download)

The HyperFlash only supports memory space, while the HyperRAM supports both memory and register spaces.

The HyperBus host controllers should take care for above to support both HyperFlash and HyperRAM. According to the K28F datasheet, the data strobe (DQS) is defined as input signal (not bidirectional) so it only supports the HyperFlash.

Best Regards,

Takahiro