Cyclone 10 GX AS x4 Configuration Compatibility with Infineon S25FS512S (Custom Flash Definition)

Hello Sumanth,  I can't reply in my system due to long answer(system limitation- this will be fixed in future), so I will reply here in community:

Hello Sumanth,

Thank you for providing the detailed logic analyzer observations and test environment context. Below are the clarifications and answers to your questions regarding the Cyclone 10 GX Active Serial x4 (AS x4) configuration behavior with the Infineon S25FS512S flash.

1. Does the Cyclone 10 GX configuration controller support transmitting the mandatory Mode Byte required by the EBh (Quad I/O Read) command?

No. The Cyclone 10 GX hard configuration controller (Control Block) does not generate or transmit a separate Mode Byte (also known as continuous read / XIP bits, M[7:0]) during the 0xEB (Quad I/O Fast Read) command sequence.

During Active Serial x4 configuration, the hardwired state machine inside the Cyclone 10 GX Control Block issues the following standard read transaction:

Opcode: 0xEB (1 line, 8 clock cycles)

Address: 4-byte / 32-bit address (4 lines, 8 clock cycles)

Dummy Clock Cycles: Fixed/configured clock cycles on DCLK (the FPGA does not drive active mode bits during these cycles)

Data Phase: Reads configuration bitstream data on DATA[3:0]

Because the FPGA configuration controller treats the cycles immediately following the address purely as wait/dummy cycles, it does not transmit the 8-bit mode byte pattern (M[7:0], which occupies 2 clock cycles across 4 I/O lines) required by the Infineon S25FS512S protocol.

2. Is this a known limitation of the Cyclone 10 GX configuration controller or Quartus Programmer?

This is a hardware controller architectural characteristic/limitation of the Cyclone 10 GX Control Block, not a limitation of the Quartus Programmer tool.

The Quartus Programmer is solely responsible for generating the programming image (.jic / .rpd) and programming the flash via JTAG using the Serial Flash Loader (SFL) IP.

Once programming is complete and the FPGA initiates configuration (upon power-up or nCONFIG pulse), the hard configuration engine in the Cyclone 10 GX acts as the SPI master.

The Cyclone 10 GX configuration controller was architected based on standard SPI NOR protocols (such as Micron and EPCQ-L devices), where random reads do not require a separate mode byte between the address and dummy clock cycles.

On the Infineon S25FS512S, the 0xEB command expects 2 mode cycles (8 bits on 4 lines) immediately following the address, followed by the programmed dummy/latency cycles. When the FPGA does not explicitly drive these mode cycles, the flash interprets the initial clock cycles differently or delays valid data output by 2 clock cycles relative to what the FPGA controller expects, resulting in bitstream misalignment and configuration failure.

3. Is there any supported method to modify the Quad I/O Read command sequence in the Custom Flash Definition?

No. The Custom Flash Definition XML file (used in the Quartus Programmer and Convert Programming Files based on AN229767 and Altera application notes) defines the JTAG programming parameters for the SFL IP (e.g., initialization sequences, register writes, page programming, sector erase, and verification).

It cannot modify, patch, or reprogram the hardwired configuration controller state machine inside the Cyclone 10 GX silicon. The read opcode (0x0B for AS x1, 0xEB for AS x4) and the protocol sequence issued by the FPGA during configuration are fixed in hardware.

4. Has Altera validated any Custom Flash Definition for the S25FS512S that can be shared as a reference?

Altera has not officially validated the Infineon/Cypress S25FS512S for Cyclone 10 GX Active Serial x4 configuration.

However, Altera provides a validated reference implementation for the newer Infineon/Cypress Semper family—specifically the Cypress S25HS512T with Cyclone 10 GX—in AN 1013: Using Generic QSPI Flash on Control Block-Based Devices (Section 6.1).

While the S25HS512T uses standard WRSR (0x01) register programming rather than WRAR (0x71), the configuration requirements outlined in AN 1013 apply to all control block-based devices using 1.8V 512Mb flash:

Key Technical Requirements & Recommendations

Disable EPCS/EPCQ ID Check (Mandatory):

In the Quartus Convert Programming Files tool, navigate to Advanced Options and enable "Disable EPCS/EPCQ ID check".

If this check is not disabled, the Cyclone 10 GX configuration controller expects an Altera-specific Silicon ID and aborts configuration after reading the JEDEC ID (0x9F), even if the flash is correctly programmed.

Dummy Clock Compensation Formula:

In the Infineon S25FS512S, the 0xEB command requires 2 Mode cycles (8 bits over 4 lines) followed by $N$ latency cycles configured in CR2NV[3:0].

To account for the 2 mode cycles when configuring Convert Programming Files: $$\text{Quad I/O Dummy Clocks} = \text{Flash Latency Cycles} + 2$$

For example, if CR2NV[3:0] is set to 8 latency cycles, the Quad I/O mode dummy clock parameter in Convert Programming Files must be set to 10. If CR2NV[3:0] is set to 6 latency cycles, the dummy clock setting should be 8.

Non-Volatile Register Settings for S25FS512S:

CR1NV = 0x02: Enables Quad I/O (QUAD bit = 1).

CR2NV = 0x88: Enables 4-byte addressing on power-up (bit 7 = 1) and sets latency code to 8 cycles (CR2NV[3:0] = 1000b), while keeping QPI disabled (bit 6 = 0). Note: Cyclone 10 GX requires 4-byte addressing upon power-up for flash densities >128 Mb (AN 1013, Section 3.2.2).

CR3NV = 0x08: Configures uniform 256-KB sector architecture (UNHYSA bit = 1) to eliminate hybrid 4-KB parameter sectors.

Recommended Workarounds / Path Forward:

Use Active Serial x1 (AS x1): Because AS x1 uses standard Fast Read (0x0B) with 8 dummy cycles and does not require mode cycles, it is fully compatible with the S25FS512S and avoids the Quad I/O mode byte incompatibility.

Supported Flash Alternatives: For applications requiring full Active Serial x4 bandwidth and guaranteed compatibility, consider selecting a tested third-party flash device from the Altera Device Configuration Support Center, such as the Cypress S25HS512T (documented in AN 1013) or supported Micron MT25QU / Macronix devices.

Best regards,
Farabi