User Manual

12311-MRB
12311 Development Hardware Reference Manual, Rev. 1
Freescale Semiconductor 3-11
3.3.2 IO Connectors J2 and J3
The two IO connectors J14 and J15 are standard 100 mil pin headers mounted on the back (non-component
side) of the 12311-MRB.The primary header J15 is 20-pin and the secondary header J14 is 18-pin, and
they are mounted physically in such a manner as to prevent reverse insertion of the 12311-MRB into a
motherboard receptacle (see Figure 3-2). When the TWR-RF, 1323x-RCM or 1323x-REM or custom
motherboard is plugged into these connectors, they allow access to MC12311 MCU GPIO.
• V_BRD is the connector supply voltage.
— Depending on power supply configuration, this voltage may supply the 12311-MRB from the
motherboard or the 12311-MRB may supply this voltage to the motherboard. See Section 3.3.1,
“Power Management”.
— Peripherals IO to the MC12311 and the MC12311 supply should use this same voltage
NOTE
The TWR-RF, 1323x-RCM and 1323x-REM and 12311-MRB are supplied
configured for the motherboard to supply main power.
• Some of the GPIO are shared with onboard devices. Check for the 12311-MRB schematic and
Table 3-4 and Table 3-5 for any conflict.
• BDM port signal PTA4/BKGD is NOT connected to the IO headers to prevent possible interference
with the debug port.
Table 3-4. 20 Pin Connector
Header Pin
Number
MC12311 Pin Name Description
1 V_BRD VDD supply to module
2NC
3 GND Module ground
4NC
5 PTB1/TXD UART TXD input to MCU
6NC
7 PTB0/RXD UART RXD Output from MCU
8NC
9 PTA7 GPIO / Timer IO
10 RESET MCU Reset
11 PTA2/SDA I2C Bus data signal (SDA)
12 PTD4/KBI2P4 UART flow control RTS input into MCU (implemented in Freescale software)
13 PTA3/SCL I2C Bus clock signal (SCL)
14 PTD3/KBI2P UART flow control CTS output from MCU (implemented in Freescale software)
15 GND Module ground
16 DIO5/CLKOUT Reference Crystal Oscillator