Interfacing an External SPI Device with the CYUSBS234/236 DVK – KBA92331

Version: *A

 

Question: How can you connect an external SPI device to the CYUSBS234/236 DVK?

 

Answer:

TheCYUSBS234 DVK has one Serial Communication Block (SCB) that can be configured as SPI, while the CYUSBS236 DVK has two SCBs (SCB0 and SCB1) that can be configured as SPI. By default, the SPI lines of the SCBs on both the DVKs are connected to the on-board SPI EEPROM(s) through jumpers (J17, J19, J20, and J21 for CYUSBS234; J17, J19, J20, J21, J24, J25, J26, and J27 for CYUSBS236). Table 1 provides details on the location of the SPI pins available on both of the DVKs and how to connect them for interfacing external SPI devices.

Table 1. SPI Pin Mapping

                                                                                                                                                                                                                     
         CYUSBS234    CYUSBS236
         SCB    SCB0    SCB1
         On Board SPI
    EEPROM
    External SPI device    On Board SPI
    EEPROM
    External SPI
    device
    On Board SPI
    EEPROM
    External SPI
    device
    SSEL    Short Pin No:2
    and 3 of J19
    Remove the Jumper
    present on J19.
    Connect the SSEL
    line of the external
    SPI device to Pin
    No: 2 of J19
    Short Pin No:2
    and 3 of J19
    Remove the Jumper
    present on J19.
    Connect the SSEL
    line of the external
    SPI device to Pin
    No: 2 of J19
    Short Pin No:2
    and 3 of J26
    Remove the Jumper
    present on J26.
    Connect the SSEL
    line of the external
    SPI device to Pin
    No: 2 of J26
    SCLK    Short Pin No:2
    and 3 of J21
    Remove the Jumper
    present on J21.
    Connect the SCLK
    line of the external
    SPI device to Pin
    No: 2 of J21
    Short Pin No:2
    and 3 of J21
    Remove the Jumper
    present on J21.
    Connect the SCLK
    line of the external
    SPI device to Pin
    No: 2 of J21
    Short Pin No:2
    and 3 of J27
    Remove the Jumper
    present on J27.
    Connect the SCLK
    line of the external
    SPI device to Pin
    No: 2 of J27
    MISO    Short Pin No:2
    and 5 of J17
    Remove the Jumper
    present on J17.
    Connect the MISO
    line of the external
    SPI device to Pin
    No: 2 of J17
    Short Pin No:2
    and 5 of J17
    Remove the Jumper
    present on J17.
    Connect the MISO
    line of the external
    SPI device to Pin
    No: 2 of J17
    Short Pin No:2
    and 5 of J24
    Remove the Jumper
    present on J24.
    Connect the MISO
    line of the external
    SPI device to Pin
    No: 2 of J24
    MOSI    Short Pin No:2
    and 5 of J20
    Remove the Jumper
    present on J20.
    Connect the MOSI
    line of the external
    SPI device to Pin
    No: 2 of J20
    Short Pin No:2
    and 5 of J20
    Remove the Jumper
    present on J20.
    Connect the MOSI
    line of the external
    SPI device to Pin
    No: 2 of J20
    Short Pin No:2
    and 5 of J25
    Remove the Jumper
    present on J25.
    Connect the MOSI
    line of the external
    SPI device to Pin
    No: 2 of J25

You can connect the SSEL, SCLK, MISO, and MOSI lines of the external device to the pin numbers given in Table 1. Refer to the CYUSBS234/236 DVK schematics for more details about the jumpers:

CYUSBS234 USB TO SERIAL DVK BOARD

CYUSBS236 USB TO SERIAL DVK BOARD

Figure 1. SPI Connection of CY7C65211

Figure 2. SPI connection of CY7C65215