Target Board Information STMicroelectronics STb710x Reference Board (mb442)

STb7100 Reference board

This board is reference design for a STb7100 based set-top-box. Thus the STb7100 is usually (but not always) soldered down. Frequently this board is supplied with no silk screening, so take care to check the location and orientation of connectors and switches.

This board was designed by the CoCo organisation (hence its name), although it was later adopted by STS and gained the board identifier mb442.

This board can also take a STb7109, in which case a second Ethernet connection is available using the STb7109's on-chip MAC with an external STE100P PHY.

For more details on identifying the mb442 please see the version information page.

Hardware Setup

Switch settings

The STb7100 Reference Board shares the same switch settings as other STb710x boards.

Serial ports

EMI Config

Known problems

External crystal selection

You may need to modify the kernel configuration for a 7100 Reference (COCO) board, depending on the value of one of the 3 crystals on board. Locate the 3 crystals, and note their values.

From kernel release 2.6.11_st2.0-22 this frequency can be set through a kernel configuration option: CONFIG_SH_EXTERNAL_CLOCK. This option can be selected through the kernel configuration option:

System type --> External clock

For earlier kernels this change requires manually editing the config files. If the crystal near the UDI connector is 30MHz (default for European boards), then no further changes to the kernel need to be applied - just build it as normal. If on the other hand the crystal near the UDI connector is 27MHz (default for AP boards), then an additional configuration change is required to the kernel before it is built.

For boards with 27MHz crystals, please edit the following file, in the kernel source tree you are building the kernel: arch/sh/Kconfig

Find the following lines (circa line number 900):

config SH_EXTERNAL_CLOCK
    int
    depends on CPU_SUBTYPE_ST40
    default "30000000" if SH_STB7100_REF
    default "27000000"

Comment out the line with 30000000 on it, by prepending it with a hash (pound) character, so it looks like the following:

config SH_EXTERNAL_CLOCK
    int
    depends on CPU_SUBTYPE_ST40
#   default "30000000" if SH_STB7100_REF
    default "27000000"

Save it, then build the kernel as normal.

Use of the second I2C bus

The Linux kernel (from release stm20-32) disables the I2C support for SSC1 on the 7100-ref (CoCo) board.

This is necessary because, contrary to the datasheet, SSC1 is not available for use as an I2C bus because there is a permanently active SPI serial FLASH device attached to this bus that cannot be disabled without a board modification.

If you wish to use this I2C bus via the header, then desolder and lift the /CS pin 1 of the M25P10-A device attached to this bus and connect it to Vcc (pin 8). An even better solution would be to connect /CS to a PIO pin so that the device could still be used.