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SPI-header pinouts

EVC2 SPI-header (2x4-pin 2.54mm pitch)

The pinout is for reference also printed at the back of the PCB. This is a standard layout matching most SOIC8/DIP8 SPI NOR Flash parts (pin numbering may be in a different sequence) and works with many adapters or test clips.

Pin#1 - CSn (Chip Select, n = active low)
Pin#2 - SPI Vcc
Pin#3 - MISO (Master-In Slave-Out)
Pin#4 - HOLDn
Pin#5 - WPn (Write Protect)
Pin#6 - SCK (Serial Clock)
Pin#7 - GND (Ground)
Pin#8 - MOSI (Master-Out Slave-In)

ASUS SPI-header (2x5-pin 2.0mm pitch)

There's a header on some ASUS motherboards with the same number of pins and keying, which is not a SPI-header but a reduced TPM-header for LPC debug. The SPI-header is usually nearby the BIOS chip and the LPC/TPM-header is usually near the bottom PCB edge. On ASUS motherboards with dual BIOS chips, there's a 3-pin 2.54mm header nearby which selects the BIOS chip. It must have a jumper placed in position 1-2 (BIOS #1) or 2-3 (BIOS #2) before it's possible to access the SPI Flash.

Pin#1 - NC (Not Connected)
Pin#2 - WPn
Pin#3 - SPI VCC
Pin#4 - Ground
Pin#5 - CSn
Pin#6 - SCK
Pin#7 - MISO
Pin#8 - MOSI
Pin#9 - HOLDn
Pin#10 - Key pin (blocked)

(Pin#1 is indicated by the white L-square mark)

MSI SPI-header (2x6-pin 2.0mm pitch)

Pin#1 - SPI Vcc
Pin#2 - SPI Vcc
Pin#3 - MISO
Pin#4 - MOSI
Pin#5 - CSn
Pin#6 - SCK
Pin#7 - GND
Pin#8 - GND
Pin#9 - NC
Pin#10 - Key pin
Pin#11 - WPn
Pin#12 - HOLDn

ASRock SPI-header (2x5-pin 2.54mm pitch)

The ASRock header has an additional pin for RSMRST# on Intel-boards which holds the PCH in reset when pulled low. This helps avoid conflicts when accessing the SPI Flash part. The additional pin is wired as a separate 1-pin 2.54mm connector on the provided cable for ASRock motherboards. It's recommended that this pin is connected to any ground pin on the EVC2 or the motherboard itself if accessing the SPI Flash part when the system is not running.

Pin#1 - WPn
Pin#2 - HOLDn
Pin#3 - CSn
Pin#4 - SPI Vcc
Pin#5 - MISO
Pin#6 - Key pin
Pin#7 - RSMRST# (Resume Reset, active low, connect to GND)
Pin#8 - SCK
Pin#9 - GND
Pin#10 - MOSI

Test-clip SOIC8/SOP8 (2x5-pin 2.54mm pitch IDC)

The available test-clip pinout matches the EVC2 SPI-header and plugs straight in from the top, leaving pin#9/10 unplugged. Pin#1 is indicated by the red wire.

Pin#1 - CSn
Pin#2 - SPI Vcc
Pin#3 - MISO
Pin#4 - HOLDn
Pin#5 - WPn
Pin#6 - SCK
Pin#7 - GND
Pin#8 - MOSI
Pin#9 - NC
Pin#10 - NC

Why is there no Gigabyte cable provided?

Gigabyte motherboards currently does not have any header present for accessing the BIOS chip. The SOIC8 test clip can be used instead on many of their motherboards, depending on the package type and spacing.

What about DIP8 parts?

Primarily older motherboard models use SPI Flash with this type of package. If there's enough interest in supporting this, a simple adapter board could be developed.

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I need to update my ASUS KRPA-U16 BIOS via SPI, it is the only way as there is no USB BIOS Flasback or BCM option. I need an old CPU which I can not find. Anyway, do you know which pins should be connected to the Raspberry Pi 4?