One-Time Programmable (OTP) Memory

The Plus1 features 128 bytes of one-time programmable (OTP) memory. This special memory area can be used to record data that will not change.

To write to the OTP memory, you'll need:

• OTP Tool (click here to download)
• A DC power source capable of delivering 2.5V

Write Procedure

To write to the OTP memory, you'll need physical access to the host board. The following instructions assume that board is a Size 3 Linux Tibbo Project PCB (LTPP3), Gen. 2. If your Plus1 is installed on a custom PCB, please refer to the SP7021 datasheet for details regarding to which pin you'll need to apply voltage.

1. Apply 2.5V to CN4
2. Open the OTP Tool
3. Click File > Open File
1. Select the OTP table file
2. Click Open
4. Click Setting > COM Port
1. Select the COM Port for your LTPP3(G2)
2. Select a baudrate of 115200
3. Click OK
5. Click Connect
6. Power on the LTPP3(G2)
7. Click Read
8. Click the checkbox in the Bit column for the section to which you will write
9. Input the data you will write to this section in the write column
10. Click Write

Reading OTP Memory

To read the entire OTP memory, run this command from a terminal on your system:

hexdump /sys/bus/nvmem/devices/sp-ocotp0/nvmem

If you just need to see the serial number, which is a limited portion of the OTP memory, run:

cat /proc/cpuinfo