CYW20702
4.5 One-Time Programmable Memory
The CYW20702 includes a One-Time Programmable (OTP) memory, allowing manufacturing customization and avoiding the need
for an on-board NVRAM.If customization is not required, then the OTP does not need to be programmed. Whether the OTP is
programmed or not, it is disabled after the boot process completes to save power.
The OTP size is 128 bytes.
The OTP is designed to store a minimal amount of information. Aside from OTP data, most user configuration information will be
downloaded into RAM after the CYW20702 boots up and is ready for host transport communication. The OTP contents are limited to:
■ Parameters required prior to downloading user configuration to RAM.
■ Parameters unique to each part and each customer (i.e., the BD_ADDR, software license key, and USB PID/VID).
The OTP memory is particularly useful in a PC design with USB transport capability because:
■ Some customer-specific information must be configured before enumerating the part on the USB transport.
■ Part or customer unique information (BD_ADDR, software license key, and USB PID/VID) do not need to be stored on the host
system.
4.5.1 Contents
The following are typical parameters programmed into the OTP memory:
■ BD_ADDR
■ Software license key
■ USB PID/VID
■ USB bus/self-powered status
■ Output power calibration
■ Frequency trimming
■ Initial status LED drive configuration
The OTP contents also include a static error correction table to improve yield during the programming process as well as forward error
correction codes to eliminate any long-term reliability problems. The OTP contents associated with error correction are not visible by
customers.
4.5.2 Programming
OTP memory programming takes place through a combination of Cypress software integrated with the manufacturing test software
and code embedded in CYW20702 firmware.
Programming the OTP requires a 3.3V supply. The OTP programming supply comes from the VDD_USB pin. For applications where
the OTP is most useful, such as the USB transport application for the PC market, the 3.3V is already required for USB operation from
the VDD_USB pin. The OTP power supply is allowed to be as low as 1.8 V to be able to read the contents. See Table 3 for the OTP
memory programming supply voltage requirements.
The OTP is enabled by default by setting OTP_DIS to low using an internal pull-down resistor. Leave this pin floating for a default
configuration. To disable the OTP, set the OTP_DIS pin to active high. This pin can be configured from the HW to enable or disable
OTP.
Typically it won’t be necessary to disable the OTP memory, even if it is not programmed during manufacturing. The OTP_DIS package
ball only needs to be tied to high if recommended by Cypress.
Table 3. OTP Programming Supply Voltage Requirementsa
Supply
VDD_USB
Minimumb
Typical
Maximumb
Unit
TBD
TBD
TBD
V
a. The average and peak current consumptions during OTP memory programming are 20 mA and 70 mA, respectively.
b. Contact your Cypress representative for recommended minimum and maximum supply voltages.
Document Number: 002-14773 Rev. *L
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