nrf52832 spi master's max transfer size at once is 255

RE: nrf52832 spi master's max transfer size at once is 255

awneil — Fri, 12 Jul 2019 10:27:48 GMT

[quote userid="81580" url="~/f/nordic-q-a/49699/nrf52832-spi-master-s-max-transfer-size-at-once-is-255/198105"]it can never a transmit after 256 bytes[/quote]

Nonsense - of course it can!

[quote userid="81580" url="~/f/nordic-q-a/49699/nrf52832-spi-master-s-max-transfer-size-at-once-is-255/198105"]once my data divide some times to transfer,the totality send time will increase[/quote]

Yes, of course it will - but that will not necessarily be a problem!

[quote userid="81580" url="~/f/nordic-q-a/49699/nrf52832-spi-master-s-max-transfer-size-at-once-is-255/198105"]the totality speed will reduce[/quote]

Yes - but, so long as it doesn't reduce by too much, that won't matter!

Which is undoubtedly what these "other company's product" are doing.

I haven't tried it - does the DMA support double-buffering ... ?

RE: nrf52832 spi master's max transfer size at once is 255

pipixia_1_1 — Fri, 12 Jul 2019 10:17:15 GMT

new a transmit

RE: nrf52832 spi master's max transfer size at once is 255

pipixia_1_1 — Fri, 12 Jul 2019 10:16:37 GMT

yes ,it can never a transmit after 256 bytes,but once my data divide some times to transfer,the totality send time will increase，in other words，the totality speed will reduce .tanks for your reply.

RE: nrf52832 spi master's max transfer size at once is 255

awneil — Fri, 12 Jul 2019 10:06:58 GMT

[quote userid="81580" url="~/f/nordic-q-a/49699/nrf52832-spi-master-s-max-transfer-size-at-once-is-255/198101"]what make me confuse is that other company's product' screen slip very fast by 52832[/quote]

I don't understand what you mean by that.

AIUI, The 256-byte limit is just the maximum you can do in a single DMA transfer - it doesn't mean that the nRF52832 can never transmit more than 256 bytes!

As noted earlier, you can simply use multiple transfers when you need >256 bytes total.

RE: nrf52832 spi master's max transfer size at once is 255

pipixia_1_1 — Fri, 12 Jul 2019 09:58:48 GMT

thanks for your reply,what make me confuse is that other company's product' screen slip very fast by 52832. as you say ,i really dont know how does they do it.

RE: nrf52832 spi master's max transfer size at once is 255

awneil — Fri, 12 Jul 2019 09:41:53 GMT

AIUI, This is a limit of the nRF52832 hardware - you can't get around it in software (other than by sending multiple 256-byte transmissions)

I think the nRF52810 also has the larger transfer capability - if your application will fit within its other constraints ...