Backplane Overall Requirements

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Pin #	MCU Label	Type	Default / Alternate Function	Notes
1	DVCC	Power	Digital Supply Voltage (3.3 V)	MCU power rail
2	DVSS	Power	Digital Ground	MCU ground
3	AVCC	Power	Analog Supply Voltage	Often tied to 3.3 V for ADC
4	AVSS	Power	Analog Ground	Ground reference for ADC
5	XIN	OSC In	Crystal Input (possible)	If external low/high freq crystal used
6	XOUT	OSC Out	Crystal Output (possible)	If external low/high freq crystal used
7	TEST / SBWTDIO	JTAG / SBW	Test Mode / JTAG Data	Used for programming / debug (Spy-Bi-Wire)
8	RST / SBWTCK	Reset / JTAG	Reset Pin / JTAG Clock	Usually active-low reset or Spy-Bi-Wire clock
9	P1.0 / TA0.1 (TBD)	GPIO / Timer	Timer A capture/compare, or general I/O	Label from schematic if different
10	P1.1 / TA0.2 (TBD)	GPIO / Timer	Timer A capture/compare, or general I/O
11	P1.2 / TA1.0 (TBD)	GPIO / Timer	Timer A capture/compare, or general I/O
12	P1.3 / TA1.1 (TBD)	GPIO / Timer	Timer A capture/compare, or general I/O
13	P1.4 / TA1.2 (TBD)	GPIO / Timer	Timer A capture/compare, or general I/O
14	P1.5 / UCB0CLK (TBD)	GPIO / SPI/I2C	SPI clock (possible), or I2C if reconfigured
15	P1.6 / UCB0SIMO (TBD)	GPIO / SPI/I2C	SPI Master Out / Slave In, or I2C data (SDA)
16	P1.7 / UCB0SOMI (TBD)	GPIO / SPI/I2C	SPI Master In / Slave Out, or I2C data
17	P2.0 / UCB0STE (TBD)	GPIO / SPI	SPI STE (chip select), or general I/O
...	...	...	...	Extend as needed for all pins on your MCU

Pin	Name	Type	Description / Notes
1	ALERT	Digital Output	Alerts MCU when a threshold or conversion event occurs. Can be configured in the ADS7138 registers.
2	ADDR	Input	Sets I²C address. Connected via resistor(s) to AVDD, GND, or left floating for different address options.
3	DECAP	Decoupling Pin	Connect to ground through a 1 μF capacitor (per datasheet) for internal regulator stability.
4	SCL	I²C Clock	I²C clock input from MCU. Requires pull-up resistor to 3.3 V (or system voltage).
5	SDA	I²C Data	I²C data line to/from MCU. Also requires pull-up resistor.
6	DVDD	Power (Digital)	1.8 V or 3.3 V digital supply pin. Check datasheet for acceptable range.
7	AVDD	Power (Analog)	3.3 V analog supply pin. Bypass with 100 nF and 1 μF capacitors close to pin.
8	GND	Ground	System ground reference.
9	AIN0 / GPIO0	Analog Input	Channel 0 input. In your schematic, may be tied to signals like ADCS_I_SENSE or IMAGER_I_SENSE, etc.
10	AIN1 / GPIO1	Analog Input	Channel 1 input. Possible net: 5V_SENSE, 3V3_SENSE, etc.
11	AIN2 / GPIO2	Analog Input	Channel 2 input.
12	AIN3 / GPIO3	Analog Input	Channel 3 input.
13	AIN4 / GPIO4	Analog Input	Channel 4 input.
14	AIN5 / GPIO5	Analog Input	Channel 5 input.
15	AIN6 / GPIO6	Analog Input	Channel 6 input.
16	AIN7 / GPIO7	Analog Input	Channel 7 input. Possibly used for Transceiver_I_SENSE, Yeast_I_SENSE, etc.
-	Thermal Pad	GND (Exposed)	Must be soldered to PCB ground plane for thermal and electrical performance.