OLIMEX© 2017
PIC32-EMZ64 user's manual
USB_DEV is a female micro B USB connector. In order to enable USB_DEV connector change all
jumpers to the opposite position: DEV_DM; DEV_DP; DEV_ID. Doing so would also disable
USB_HOST. The pinout of the micro USB is visible below:
Pin #
Signal name
Processor pin
1
+5V_HOST_PWR
-
2
USB_HOST_DM
36
3
USB_HOST_DP
37
4
USB_DEV_ID
38
5
GND
-
Leaving all three jumpers open simultaneously would disable both USB connectors. This might be
faster way to disable an active USB connection in some cases.
6.3.3 UEXT
The 10-pin UEXT connectors are typically mounted on Olimex boards. They pack three common
interfaces in a single connector – UART, I2C and SPI. You can use the UEXT connector to access
this interfaces easier (via jumper wires, for example).
You can also connect expansion modules to the UEXT connectors. More on UEXT might be found
here:
https://www.olimex.com/Products/Modules/UEXT/
Note that you should not provide power to the UEXT connector. Pin #1 of the UEXT (3.3V) is
output.
Pin #
Wire name
Function
1
3.3V
Power output
2
GND
Power output
3
RD4/U4TX
UART
4
RD0/U4RX
UART
5
RG8/SCL4
I2C
6
RG7/SDA4
I2C
7
RD11/SDI4(MISO4)
SPI
8
RD5/SDO4(MOSI4)
SPI
9
RD10/SCK4
SPI
10
RD9/#SS4
SPI
The design includes several pull up resistors on the data lines available at the UEXT:
1) a 10K pull up on the UART RD line (pin #4). There is also Schottky diode on the same line.
2) 2.2K pull ups on the I2C lines (pins #5 and #6)
3) a 10K pull up on the SPI SS line (pin #10)
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