SPI flash on-board programming using XHRA-2HPA

[AndersHa]

Hi guys,

Does the XHRA-2HPA allow ISP (on-board prgramming/In-System Programming) of the attached QSPI flash? In other words - are the outputs of the XHRA-2HPA to the QSPI flash tristated during reset? (I guess reset is the only option as there is no prog pin on the device)

If ISP is not supported, I guess external logic is needed to support ISP. Any comments/ideas?

/Anders

[infiniteimprobability]

are the outputs of the XHRA-2HPA to the QSPI flash tristated during reset?

Yes - as with most things in Xmos, the QSPI interface is software defined. This means the XHRA chip won't configure those ports until it executes the boot ROM. So while held in reset, the ports will be tristated and you are free manipulate the pins externally.

[AndersHa]

Prefect :-) Thanks for a fast and accurate answer.

BR Anders

[henk]

Just for completeness: the pins are not driven, but during reset a weak pull-down is enabled bringing them to a defined state.

[infiniteimprobability]

Good point. We recommend driving with at most 3k3 impedance to overcome the internal weak pull downs. Should be no issue for a typical output buffer..