MMA7455L breakout board manufacturing tests
From DP
Contents |
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
This test uses the Bus Pirate to check the MMA7455 during manufacturing.
Options
[help menu]
Success
Failure
--------------------- Starting a new Test-------------------------
Opening Bus Pirate on COM5 at 115200bps...
Configuring Bus Pirate ....
Going into Binary Bitbang mode..
Entering binary mode...ok
Going into SPI mode.. Switching to SPI mode ..ok
Power on...
Enabling power, normal pin outputs..
CS High : 0x03....
CS Low : 0x02....
Sending 0x1A....
Got reply: 0X1D
Self test status with MMA7455L breakout board: **** PASS! *****
CS High : 0x03....
Exiting SPI mode/reseting Buspirate..
Successful test.
Notes
The automated test app uses the Bus Pirate to test the connection to the MMA7455L:
- Enter BBIO mode
- Enter SPI mode
- Enable power, normal pin outputs
- Set CS high
- Set CS low
- Send 0x1A
- Read one byte
- Set CS high
- Verify read=0x1D
- Exit SPI mode (to disable power and pins)
- Repeat from 2