Pmod SF2 Reference Manual


The Pmod SF2 has been replaced by the Pmod SF3.

The Digilent Pmod SF2 (Revision A) provides 16MB of serial phase change memory (PCM).

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  • 16MB of serial phase change memory (PCM)
  • 128Mbit, quad/dual/single serial interface
  • More than 1,000,000 write cycles
  • 8 Super Page programming regions for a total of 128 sectors
  • 12-pin Pmod connector with SPI interface

Functional Description

The Pmod SF2 utilizes Micron's P5Q PCM to provide easily accessed non-volatile memory to system boards. As PCM supports bit-alterable page writes it lasts much longer than flash memory and can support over 1,000,000 page write cycles per sector.

Interfacing with the Pmod

The Pmod SF2 communicates with the host board via the SPI protocol. By bringing the Chip Select line logic level low voltage, users may issue a single byte instruction code to memory chip. A table of available commands taken from the P5Q datasheet is provided below:

Instruction Description One-Byte Instruction Code Number of Address Bytes Number of Dummy Bytes Number of Data Bytes
WREN Write Enable 0x06 0 0 0
WRDI Write Disable 0x04 0 0 0
RDID Read Identification 0x9F 0 0 1 to 3
0x9E 0 0 1 to 3
RDSR Read Status Register 0x05 0 0 1 to ∞
WRSR Write Status Register 0x01 0 0 1
READ Read Data Bytes 0x03 3 0 1 to ∞
FAST_READ Read Data Bytes at Higher Speed 0x0B 3 1 1 to ∞
DOFR Dual Output Fast Read 0x3B 3 1 1 to ∞
QOFR Quad Output Fast Read 0x6B 3 1 1 to ∞
PP Page Program (Legacy) 0x02 3 0 1 to 64
Page Program (Bit-alterable write) 0x22 3 0 1 to 64
Page Program (On all 1's) 0xD1 3 0 1 to 64
DIFP Dual Input Fast Program (Legacy) 0xA2 3 0 1 to 64
Dual Input Fast Program (Bit-alterable write) 0xD3 3 0 1 to 64
Dual Input Fast Program (On all 1's) 0xD5 3 0 1 to 64
QIFP Quad Input Fast Program (Legacy) 0x32 3 0 1 to 64
Quad Input Fast Program (Bit-alterable write) 0xD7 3 0 1 to 64
Quad Input Fast Program (On all 1's) 0xD9 3 0 1 to 64
SE Sector Erase 0xD8 3 0 0
BE Bulk Erase 0xC7 0 0 0
DP Deep Power-down 0xB9 0 0 0

The memory address bits range from 0x000000 to 0xFFFFFF with each individual page consisting of 64 bytes apiece. Users that wish to simply use the memory module without concerning themselves with the dual/quad input and output communication may use the same library that is available for the PmodSF without any issue.

Pinout Description Table

Pin Signal Description Pin Signal Description
1 ~CS Chip Select 7 NC Not Connected
2 MOSI/DQ0 Master-Out-Slave-In 8 W/DQ2 Write Protect
3 MISO/DQ1 Master-In-Slave-Out 9 HLD/DQ3 Hold
4 SCK Serial Clock 10 NC Not Connected
5 GND Power Supply Ground 11 GND Power Supply Ground
6 VCC Power Supply (3.3V) 12 VCC Power Supply (3.3V)

Any external power applied to the Pmod SF2 must be within 2.7V and 3.6V; it is strongly recommended that Pmod is operated at 3.3V.

Physical Dimensions

The pins on the pin header are spaced 100 mil apart. The PCB is 1 inch long on the sides parallel to the pins on the pin header and 0.8 inches long on the sides perpendicular to the pin header.

Additional Information

The schematics of the Pmod SF2 are available here. Additional information about the PCM module including communication modes and specific timings of the chip can be found by checking out its datasheet here.

Example code demonstrating how to get information from the Pmod SF2 can be found here.

If you have any questions or comments about the Pmod SF2, feel free to post them under the appropriate section (“Add-on Boards”) of the Digilent Forum.