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Diffstat (limited to 'Documentation/spi/spi-lm70llp')
| -rw-r--r-- | Documentation/spi/spi-lm70llp | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/Documentation/spi/spi-lm70llp b/Documentation/spi/spi-lm70llp index 154bd02220b..463f6d01fa1 100644 --- a/Documentation/spi/spi-lm70llp +++ b/Documentation/spi/spi-lm70llp @@ -13,10 +13,20 @@ Description This driver provides glue code connecting a National Semiconductor LM70 LLP temperature sensor evaluation board to the kernel's SPI core subsystem. +This is a SPI master controller driver. It can be used in conjunction with +(layered under) the LM70 logical driver (a "SPI protocol driver"). In effect, this driver turns the parallel port interface on the eval board into a SPI bus with a single device, which will be driven by the generic LM70 driver (drivers/hwmon/lm70.c). + +Hardware Interfacing +-------------------- +The schematic for this particular board (the LM70EVAL-LLP) is +available (on page 4) here: + + http://www.national.com/appinfo/tempsensors/files/LM70LLPEVALmanual.pdf + The hardware interfacing on the LM70 LLP eval board is as follows: Parallel LM70 LLP @@ -36,7 +46,7 @@ The hardware interfacing on the LM70 LLP eval board is as follows: Note that since the LM70 uses a "3-wire" variant of SPI, the SI/SO pin is connected to both pin D7 (as Master Out) and Select (as Master In) -using an arrangment that lets either the parport or the LM70 pull the +using an arrangement that lets either the parport or the LM70 pull the pin low. This can't be shared with true SPI devices, but other 3-wire devices might share the same SI/SO pin. |