EPCQ-A devices offer the following features:

• Serial or quad-serial FPGA configuration in devices that support active serial (AS) x1 or AS x4¹ configuration schemes
• Low cost, low pin count, and non-volatile memory
• 2.7-V to 3.6-V operation
• Available in 8-pin small-outline integrated circuit (SOIC) package for EPCQ4A, EPCQ16A, and EPCQ32A devices
• Available in 16-pin SOIC package for EPCQ64A and EPCQ128A devices
• Reprogrammable memory more than 100,000 program-erase cycles
• Write protection support for memory sectors using status register bits
• Fast read, extended dual input fast read, and extended quad input fast read of the entire memory using a single operation code
• Reprogrammable with an external microprocessor using the SRunner software driver
• In-system programming (ISP) support with the SRunner software driver
• ISP support with Intel^® FPGA Download Cable II, Intel^® FPGA Download Cable, or Intel^® FPGA Ethernet Cable
• By default, the memory array is erased and the bits are set to 1
• More than 20-year data retention
• Supports JEDEC standard Serial Flash Discoverable Parameter (SFDP)

The EPCQ4A, EPCQ16A, and EPCQ32A devices are available in 8-pin SOIC packages. The EPCQ64A and EPCQ128A devices are available in 16-pin SOIC packages.

This section describes the operations that you can use to access the memory in EPCQ-A devices. When performing the operation, addresses and data are shifted in and out of the device serially, with the MSB first.

When the active low chip select (nCS) signal is driven low, shift in the operation code into the EPCQ-A device using theDATA0 pin. Each operation code bit is latched into the EPCQ-A device at rising edges of the DCLK signal.

While executing an operation, shift in the desired operation code, followed by the address or data bytes. See related information for more information about the address and data bytes. The device must drive the nCS pin high after the last bit of the operation sequence is shifted in.

For read operations, the data read is shifted out on the DATA[3:0] pins. You can drive the nCS pin high when any bit of the data is shifted out.

For write and erase operations, drive the nCS pin high at a byte boundary, that is in a multiple of eight clock pulses. Otherwise, the operation is rejected and not executed.

All attempts to access the memory contents while a write or erase cycle is in progress are rejected, and the write or erase cycle continues unaffected.

The status register can be read continuously and at anytime, including during a write or erase operations.

The write status operation does not affect the write enable latch and write in progress bits. You can use the write status operation to set the status register block protection and top or bottom bits. Therefore, you can implement this operation to protect certain memory sectors. After setting the block protect bits, the protected memory sectors are treated as read-only memory. You must execute the write enable operation before the write status operation.

Immediately after the nCS signal drives high, the device initiates the self-timed write status cycle. The self-timed write status cycle usually takes 10 ms for all EPCQ-A devices and is guaranteed to be less than 15 ms. For details about t_WS , refer to the related information below. You must account for this delay to ensure that the status register is written with the desired block protect bits. Alternatively, you can check the write in progress bit in the status register by executing the read status operation while the self-timed write status cycle is in progress. Write in progress bit is 1 during the self-timed write status cycle and 0 when it is complete.

When you execute the read bytes operation, you first drive the nCS pin low and shift in the read bytes operation code, followed by a 3-byte address (A[23..0]). Each address bit must be latched in at rising edges of the DCLK signal. After the address is latched in, the memory contents of the specified address are shifted out serially on the DATA1 pin, beginning with the MSB. For reading Raw Programming Data File (.rpd), the content is shifted out serially beginning with the LSB. Each data bit is shifted out at falling edges of the DCLK signal. The maximum DCLK frequency during the read bytes operation is 50 MHz.

The first byte address can be at any location. The device automatically increases the address to the next higher address after shifting out each byte of data. Therefore, the device can read the whole memory with a single read bytes operation. When the device reaches the highest address, the address counter restarts at 0x000000, allowing the memory contents to be read out indefinitely until the read bytes operation is terminated by driving the nCS signal high. If the read bytes operation is shifted in while a write or erase cycle is in progress, the operation is not executed and does not affect the write or erase cycle in progress.

When you execute the fast read operation, you first shift in the fast read operation code, followed by a 3-byte address (A[23..0]), and 8 dummy clock cycles with each bit being latched-in at rising edges of the DCLK signal. Then, the memory contents at that address is shifted out on DATA1 with each bit being shifted out at a maximum frequency of 100 MHz at falling edges of the DCLK signal.

The first byte address can be at any location. The device automatically increases the address to the next higher address after shifting out each byte of data. Therefore, the device can read the whole memory with a single fast read operation. When the device reaches the highest address, the address counter restarts at 0x000000, allowing the read sequence to continue indefinitely.

You can terminate the fast read operation by driving the nCS signal high at any time during data output. If the fast read operation is shifted in while an erase, program, or write cycle is in progress, the operation is not executed and does not affect the erase, program, or write cycle in progress.

This operation is similar to the fast read operation except that the data and addresses are shifted in and out on the DATA0 and DATA1 pins.

This operation is similar to the extended dual input fast read operation except that the data and addresses are shifted in and out on the DATA0, DATA1, DATA2, and DATA3 pins.

This operation reads the 8-bit device identification of the EPCQ-A device from the DATA1 output pin. If this operation is shifted in while an erase or write cycle is in progress, the operation is not executed and does not affect the erase or write cycle in progress.

The 8-bit device identification of the EPCQ-A device is shifted out on the DATA1 pin at falling edges of the DCLK signal.

This operation reads the 8-bit silicon ID of the EPCQ-A device from the DATA1 output pin. If this operation is shifted in during an erase or write cycle, it is ignored and does not affect the cycle that is in progress.

The device implements the read silicon ID operation by driving the nCS signal low and then shifting in the read silicon ID operation code, followed by three dummy bytes on the DATA0 pin. The 8-bit silicon ID of the EPCQ-A device is then shifted out on the DATA1 pin at falling edges of the DCLK signal. The device can terminate the read silicon ID operation by driving the nCS signal high after reading the silicon ID at least one time. Sending additional clock cycles on DCLK while nCS is driven low can cause the silicon ID to be shifted out repeatedly.

When you enable the write enable operation, the write enable latch bit is set to 1 in the status register. You must execute this operation before the write bytes, write status, erase bulk, erase sector, and quad input fast write bytes operations.

The write disable operation resets the write enable latch bit in the status register. To prevent the memory from being written unintentionally, the write enable latch bit is automatically reset when implementing the write disable operation, and under the following conditions:

• Power up
• Write bytes operation completion
• Write status operation completion
• Erase bulk operation completion
• Erase sector operation completion
• Quad input fast write bytes operation completion

This operation allows bytes to be written to the memory. You must execute the write enable operation before the write bytes operation. After the write bytes operation is completed, the write enable latch bit in the status register is set to 0.

When you execute the write bytes operation, you shift in the write bytes operation code, followed by a 3-byte address (A[23..0]) and at least one data byte on the DATA0 pin. If the eight LSBs (A[7..0]) are not all 0, all sent data that goes beyond the end of the current page is not written into the next page. Instead, this data is written at the start address of the same page. You must ensure the nCS signal is set low during the entire write bytes operation.

If more than 256 data bytes are shifted into the EPCQ-A device with a write bytes operation, the previously latched data is discarded and the last 256 bytes are written to the page. However, if less than 256 data bytes are shifted into the EPCQ-A device, they are guaranteed to be written at the specified addresses and the other bytes of the same page are not affected.

The device initiates a self-timed write cycle immediately after the nCS signal is driven high. For details about the self-timed write cycle time, refer to t_WB in the related information below. You must account for this amount of delay before another page of memory is written. Alternatively, you can check the write in progress bit in the status register by executing the read status operation while the self-timed write cycle is in progress. The write in progress bit is set to 1 during the self-timed write cycle and 0 when it is complete.

This operation is similar to the write bytes operation except that the data are shifted in on the DATA0, DATA1, DATA2, and DATA3 pins.

This operation sets all the memory bits to 1 or 0xFF. Similar to the write bytes operation, you must execute the write enable operation before the erase bulk operation.

You can implement the erase bulk operation by driving the nCS signal low and then shifting in the erase bulk operation code on the DATA0 pin. The nCS signal must be driven high after the eighth bit of the erase bulk operation code has been latched in.

The device initiates a self-timed erase bulk cycle immediately after the nCS signal is driven high. For details about the self-timed erase bulk cycle time, refer to t_EB in the related information below.

You must account for this delay before accessing the memory contents. Alternatively, you can check the write in progress bit in the status register by executing the read status operation while the self-timed erase cycle is in progress. The write in progress bit is set to 1 during the self-timed erase cycle and 0 when it is complete. The write enable latch bit in the status register is reset to 0 before the erase cycle is complete.

The erase sector operation allows you to erase a certain sector in the EPCQ-A device by setting all the bits inside the sector to 1 or 0xFF. This operation is useful if you want to access the unused sectors as a general purpose memory in your applications. You must execute the write enable operation before the erase sector operation.

When you execute the erase sector operation, you must first shift in the erase sector operation code, followed by the 3-byte address (A[23..0]) of the chosen sector on the DATA0 pin. The 3-byte address for the erase sector operation can be any address inside the specified sector. Drive the nCS signal high after the eighth bit of the erase sector operation code has been latched in.

The device initiates a self-timed erase sector cycle immediately after the nCS signal is driven high. For details about the self-timed erase sector cycle time, refer to t_ES in the related information below. You must account for this amount of delay before another page of memory is written. Alternatively, you can check the write in progress bit in the status register by executing the read status operation while the self-timed erase cycle is in progress. The write in progress bit is set to 1 during the self-timed erase cycle and 0 when it is complete. The write enable latch bit in the status register is set to 0 before the self-timed erase cycle is complete.

The erase subsector operation allows you to erase a certain subsector in the EPCQ-A device by setting all the bits inside the subsector to 1 or 0xFF. This operation is useful if you want to access the unused subsectors as a general purpose memory in your applications. You must execute the write enable operation before the erase subsector operation.

When you execute the erase subsector operation, you must first shift in the erase subsector operation code, followed by the 3-byte address (A[23..0]) of the chosen subsector on the DATA0 pin. The 3-byte address for the erase subsector operation can be any address inside the specified subsector. For details about the subsector address range, refer to the related information below. Drive the nCS signal high after the eighth bit of the erase subsector operation code has been latched in.

The device initiates a self-timed erase subsector cycle immediately after the nCS signal is driven high. For details about the self-timed erase subsector cycle time, refer to related the information below. You must account for this amount of delay before another page of memory is written. Alternatively, you can check the write in progress bit in the status register by executing the read status operation while the self-timed erase cycle is in progress. The write in progress bit is set to 1 during the self-timed erase cycle and 0 when it is complete. The write enable latch bit in the status register is set to 0 before the self-timed erase cycle is complete.

The Read SFDP Register operation is compatible with the JEDEC SFDP standard, JESD216A. For SFDP register values and descriptions, please refer to Appendix: SFDP Register Definitions.

Initiate the Read SFDP operation by driving the nCS pin low and shifting the operations code followed by a 3-byte address into the DATA0 pin. The 3-byte address content:

• A[23..8] = 0
• A[7..0] = Defines the starting byte address for the 256-byte SFDP register

Eight dummy clock cycles are required before the SFDP register contents are shifted out on the falling edge of the 40^th DCLK with the most significant bit (MSB) first.

EPCQ-A devices support active and standby power modes. When the nCS signal is low, the device is enabled and is in active power mode. The FPGA is configured while the EPCQ-A device is in active power mode. When the nCS signal is high, the device is disabled but remains in active power mode until all internal cycles are completed, such as write or erase operations. The EPCQ-A device then goes into standby power mode. The I_CC1 and I_CC0 parameters list the V_CC supply current when the device is in active and standby power modes.

The Intel^® Quartus^® Prime software provides programming support for EPCQ-A devices. When you select an EPCQ-A device, the Intel^® Quartus^® Prime software automatically generates the Programmer Object File (.pof) to program the device. The software allows you to select the appropriate EPCQ-A device density that most efficiently stores the configuration data for the selected FPGA.

You can program the EPCQ-A device in-system by an external microprocessor using the SRunner software driver. The SRunner software driver is developed for embedded EPCQ-A device programming that you can customize to fit in different embedded systems. The SRunner software driver reads .rpd files and writes to the EPCQ-A devices. The programming time is comparable to the Intel^® Quartus^® Prime software programming time. Because the FPGA reads the LSB of the .rpd data first during the configuration process, the LSB of .rpd bytes must be shifted out first during the read bytes operation and shifted in first during the write bytes operation.

Writing and reading the .rpd file to and from the EPCQ-A device is different from the other data and address bytes.

During the ISP of an EPCQ-A device using the Intel^® FPGA download cables, the cable pulls the nCONFIG signal low to reset the FPGA and overrides the 10-kΩ pull-down resistor on the nCE pin of the FPGA. The download cable then uses the interface pins depending on the selected AS mode to program the EPCQ-A device. When programming is complete, the download cable releases the interface pins of the EPCQ-A device and the nCE pin of the FPGA and pulses the nCONFIG signal to start the configuration process.

The FPGA can program the EPCQ-A device in-system using the JTAG interface with the serial flash loader (SFL). This solution allows you to indirectly program the EPCQ-A device using the same JTAG interface that is used to configure the FPGA.