LPC55S69 : wakeup due SPI3

EugeneHiihtaja — Mon, 27 Jan 2020 19:05:55 GMT

Hi !

SPI3 can be used as wakeup source for exit from PowerDown mode. And it works fine.

But RX fifo has size 8 items only and wakeup take > 350 us.

It means , MCU can't receive any more bytes until SPI ISR can be processed.

So I shouln't expect if more than 8 items will be in Fifo until exit from PowerDown is fully completed.

Is this so ? Or for wakeup more RX fifo can be allocated some how ?

Regards,

Eugene

Re: LPC55S69 : wakeup due SPI3

xiangjun_rong — Sun, 02 Feb 2020 02:43:29 GMT

Hi, Eugene,

You are right that the maximum FIFO size of LPC55S69 SPI module is 8, this is hardware restriction, no way to increase the SPI FIFO size.

If more than 8 data rush into the SPI FIFO before the exit from power-down is fully completed, some data will be lost.

Hope it can help you

Xiangjun Rong