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particle-iot / core

Hardware design files for the Spark Core, a tiny Wi-Fi development kit.
https://www.spark.io/
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what's the purpose of tri-state buffer on wifi module SPI_DOUT #45

Closed ghost closed 11 years ago

ghost commented 11 years ago

Hello spark team,

I have a question (not an issue) , what is the purpose of inserting a tristate buffer between wifi module pin 13 (SPI_DOUT) and STM32 host PB14 (pin 27, SPI_MISO)

it seems to me that both use 3.3V I/O's, and PB14 is dedicated to wifi and not shared with the external world

thanks Sherif

zsup commented 11 years ago

PB14 is shared with the SPI FLASH module, and the CC3000 does not tri-state, so without the buffer there is an opportunity for bus contention On Aug 23, 2013 8:55 PM, "Sherif Eid" notifications@github.com wrote:

Hello spark team,

I have a question (not an issue) , what is the purpose of inserting a tristate buffer between wifi module pin 13 (SPI_DOUT) and STM32 host PB14 (pin 27, SPI_MISO)

it seems to me that both use 3.3V I/O's, and PB14 is dedicated to wifi and not shared with the external world

thanks Sherif

— Reply to this email directly or view it on GitHubhttps://github.com/sprk/core/issues/45 .