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-rw-r--r--host/docs/usrp_e3xx.dox17
1 files changed, 11 insertions, 6 deletions
diff --git a/host/docs/usrp_e3xx.dox b/host/docs/usrp_e3xx.dox
index 1fe37d195..cbaf505f1 100644
--- a/host/docs/usrp_e3xx.dox
+++ b/host/docs/usrp_e3xx.dox
@@ -723,14 +723,14 @@ will look like this:
# [...]
\endcode
-\section e3xx_gpio The Front-Panel GPIO
+\section e3xx_gpio Internal or Front-Panel GPIO
\b Note: Do not source high currents (more than 5 mA) per pin. The GPIOs are not
designed to drive high loads!
-\b Note: Unlike the X300 series, the E3XX series does not have user-programmable
-daughterboard GPIOs. The front-panel GPIOs can still be used to track the ATR
-state of the radios, though (see below).
+\b Note: Unlike the X300 series, the E3XX series does not have
+user-programmable daughterboard GPIOs. The front-panel (or internal) GPIOs can
+still be used to track the ATR state of the radios, though (see below).
The USRP E310 has 6 programmable GPIO pins, accessible through an internal
connector (see also \ref e31x_hw_gpio). The E320 has 8 GPIO pins, accessible
@@ -1050,9 +1050,9 @@ of your device. Note that this supply voltage is turned off in order to save pow
### Pin Mapping
- Pin 1: +3.3V
-- Pin 2: Reserved
+- Pin 2: I2C SCL (3.3 V)
- Pin 3: Data[5]
-- Pin 4: Reserved
+- Pin 4: I2C SDA (3.3 V)
- Pin 5: Data[4]
- Pin 6: Data[0]
- Pin 7: Data[3]
@@ -1060,6 +1060,11 @@ of your device. Note that this supply voltage is turned off in order to save pow
- Pin 9: 0V
- Pin 10: Data[2]
+Pin 1 is connected to the shared +3.3V power rail and can be used to draw power.
+The maximum current depends on the power used by the rest of the device, but
+300-500 mA is generally safe. It is recommended to monitor the rail voltage
+when drawing power from this pin.
+
Please see the \ref page_gpio_api for information on configuring and using the GPIO bus.
\subsection e31x_hw_chipscope Debugging custom FPGA designs with Xilinx Chipscope