How to interface Cypress CY3686 DVK to NAND Flash Memory with Four Chip Selects? - KBA89951

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    Question: How to interface Cypress CY3686 DVK to NAND Flash Memory with Four Chip Selects?



    The Samsung K9NCG08U5M (64 Gbit) and K9WBG08U5M (32 Gbit) are NAND flash memory devices in a 48-pin TSOP stacked package, each consisting of four separate memory dies of 16 Gb and 8 Gb, respectively. While interfacing such memory devices with CY3686 development kit (DVK), each of the dies in the device requires an individual Chip Enable (CE) input and an individual Ready or Busy (R/B) output. The Cypress CY3686 DVK board contains eight separate 48-pin TSOP sockets. These sockets, however, only accept single package chips and have the connections for only two CE inputs and two R/B outputs.

    The CY3686 DVK requires an adapter board to support the extra mechanical and electrical requirements of NAND flash devices with a higher number (4 or 8) of chip enables.

    Adapter Board

    Following are the details of an adapter board with a socket that accepts stacked packages and provides access to all 48 pins:

    •   Website :
    •   Product Code : [TO1]
    •   Product Name : Head SOP32, 40, 48LD Socket(A)
    •   Image : See Figure 1.
    Figure 1. 48-Pin TSOP Adapter Board

    Wiring Connections

    Table 1 lists the required signal connections between Samsung NAND devices and Cypress CY3686 DVK.

    Table 1. NAND Flash and CY3686 Signal Connections
        NAND Flash    CY3686
        Name    Pin    Name    Port Pin:
        R/ B4    4    R_nB2    P2: 4
        R/ B3    5    R_nB2    P2: 4
        R/ B2    6    R_nB1    P2: 5
        R/ B1    7    R_nB1    P2: 5
        RE    8    nXRE0    P2: 10
        CE1    9    nXCE0    P1: 11
        CE2    10    nXCE1    P1: 10
        Vcc    12    VCC_3.3    P2: 2
        Vss    13    GND    P2: 20
        CE3    14    nXCE2    P1: 9
        CE4    15    nXCE3    P1: 8
        CLE    16    CLE    P2: 19
        ALE    17    ALE    P2: 18
        WE    18    nXWE    P2: 11
        WP    19    nWP_NF    P2: 15
        I/O0    29    D0    P1: 19
        I/O1    30    D1    P1: 18
        I/O2    31    D2    P1: 17
        I/O3    32    D3    P1: 16
        Vss    36    GND    P1: 20
        Vcc    37    VCC_3.3    P1: 2
        I/O4    41    D4    P1: 15
        I/O5    42    D5    P1: 14
        I/O6    43    D6    P1:13
        I/O7    44    D7    P1:12

    The CY3686 provides only two R/B lines, each with a 2.2- KΩ pull-up resistor, which must be shared by the four R/B open-drain outputs.

    R/ B4 and R/ B3 share R_nB2, and R/ B2 and R/ B1 share R_nB1.


    Connect the adapter board as described in Table 1. Then, insert a working NAND flash device into the socket on the adapter board. Install the latest version of the NX2LP NAND Programming Utility (NandMfg.exe) on your computer, and run the utility. The latest software tools are available at CY3686 EZ-USB NX2LP-Flex™ USB 2.0 Development Kit. Connect the CY3686 to your computer using a standard USB cable.

    The NX2LP NAND Programming Utility dialog box (Figure 2) appears. The CY3686 user’s guide is installed with the software tools. Refer to the user’s guide for details on how the programming utility formats the NAND device. When the NAND device is set up and connected, it is listed as Samsung <chip number> (<chip size> Mbytes in four chips). This is because the device is actually four smaller devices physically stacked on top of each other. Information on how the firmware handles four chip selects and R/B lines are available in the application note AN61347. This document is also provided with the software.

    Figure 2. Connected and Unprogrammed Device


    To program the part with firmware:

    1.   In the File menu, click the Select Configuration option.
    2.   Load the appropriate .nx2 file.
    3.   Click the Program Device button.
         Figure 3. Programmed and Formatted Device

    The NX2LP NAND Programming Utility dialog box (Figure 3) appears after the device is programmed and formatted. The part is now ready for use