The F75223 is a BIOS Guard which can copy the BIOS code from one SPI flash to another. The F75223 provides an interface to connect 2 SPI flashes and supports manual/auto mode option.Mode option can be decided by hardware strapping (by PWROK pin) or register setting.
Two SPI flashescan be assumed to flash A and flash B. For manual mode, the F75223 controls flash A or B to read or program by the SPI host which means only one flash could be accessed by the SPI host.
For auto mode, the F75223 sequentially controls flash A and B to read or program by the SPI host. F75223 provides a watch dog timer and PWROK detect function. When system power on, the WDT function will count down to zero and the PWROK status would be detected in the meantime. Timeout or the PWROK failure will trigger the reset signal to the system and sequentially change to backup flash for booting. Also, the F75223 would alternate the flash when PWROK failure occurs.
The F75223 is programmed by SMBUS interface, and only support Byte Read/Write protocol. The chip is powered by VSB and packaged in 20 QFN Green Spec.
- FEATURES
- PACKAGE
- ATTACHMENTS
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General Functions
- Bi-directional BIOS recovery
- Manual copy by button (low pulse, de-bounce 4 seconds)
- Strap status when PWROK rising and load to state machine immediately
- 4 modes of LED status blinking (A, B, burn in from B to A or A to B)
- WDT timer (1sec ~ 16sec, default 10sec)
- PWROK counter
- Power-Down mode
- Programmable SPI command, register include Chip Erase command (0xC7)
Chip Erase command (0xC7)
Read command (0x03)
Program command(0x02)
Write enable command (0x06)
Write disable command (0x04)
Read status command (0x05)
Enable Write Status command (0x50)
Write Status command (0x01)
Long Wait time register
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Package
- 20-pin QFN Green Package