MMA7455L breakout board manufacturing tests

From DP

Contents 1 Manufacturing prototype test 1.1 Test connections 1.2 Bus Pirate setup 1.3 Check the connection 2 Automated manufacturing test 2.1 Notes

Manufacturing prototype test

This is a simple test to verify the connections on the board.

Test connections

Bus Pirate	Direction	MMA7455L	Description
MOSI	→	SDA/SDI	Master Out, Slave In
MISO	←	SDO	Master In, Slave Out
CLK	→	SCL/SPC	Clock signal
CS	→	CS	Chip Select
+3.3V	→	3.3V	Power supply
GND	↔	GND	Ground

Bus Pirate setup

Connect the Bus Pirate to the chip as shown in the table.

HiZ>m<<<mode command
1. HiZ
...
5. SPI
...
(1)>5<<<SPI mode
Select output type:
1. Open drain (H=Hi-Z, L=GND)
2. Normal (H=3.3V, L=GND)
(1)>2<<<normal pinout
Ready
SPI>

Configure the Bus Pirate for SPI mode. Chose all the default settings except output type. Choose normal pin outputs.

SPI>W<<<enable power supplies
Power supplies ON
SPI>

The chip is powered by the Bus Pirate, enable the power supplies (W).

Check the connection

SPI>[0x1A r]
/CS ENABLED
WRITE: 0x1A <<<read I2C address register
READ: 0x1D<<<read value from register
/CS DISABLED
SPI>

Enter '[0x1A r]' and verify that the READ: value is 0x1D.

Automated manufacturing test

Notes

The automated test app uses the Bus Pirate to test the connection to the MMA7455L:

1. Enter BBIO mode
2. Enter SPI mode
3. Enable power, normal pin outputs
4. Set CS high
5. Set CS low
6. Send 0x1A
7. Read one byte
8. Set CS high
9. Verify read=0x1D
10. Exit SPI mode (to disable power and pins)
11. Repeat from 2