TS-7400/TS-9441 MANUAL
HARDWARE COMPONENTS
Table: SD Card core registers
I/O Addr
Name
Description
BASE + 0
SDCMD
SD Command register
BASE + 2
SDDAT
SD Data register
BASE + 4
SDSTATE
SD State register
BASE + 6
SDCTRL
SD Control register
4.3 Glue Logic CPLD
The
TS-7400
ARM SBC's include an Altera MAXII CPLD which is responsible for taking
control of the internal components communication through glue logic implementation. For
instance, the CPLD is used to control the NAND flash through internal register
configuration.
The CPLD has a watchdog timer, interfaces to the real-time clock and controls the
EEPROM chip select. It also implements peripheral features that, together with EP9302
modules, makes available an advanced set of communication ports, DIO pins, ADC
converters, and others. The inclusion of a CPLD on the SBC
allows customized
programming for customers with special needs, without having to do a more expensive
board redesign.
The CPLD can be programmed using the TS-9441 JTAG header and special
software/hardware supporting tools. Contact Technologic Systems for support on CPLD
programming software and tools.
4.4 Real-Time Clock
The
TS-7400
optionally supports a Non-volatile Battery-backed real-time clock (RTC)
which is soldered onto the board. This option uses an ST Micro M48T86PC1 module for
the real-time clock function. This module contains the lithium battery, 32.768 kHz crystal,
and a RTC chip with 114 bytes of battery-backed CMOS RAM. It will maintain clock
operation for a minimum of 10 years in the absence of power.
The 114 bytes of non-volatile RAM, physically located in the RTC chip, are available to the
user. Contact Technologic Systems for driver support.
The RTC is accessed differently on the
TS-7400
when compared to other TS products.
DIO on the EP9302 are wired to pins on the RTC and must be accessed by twiddling the
DIO in the correct manner. At the time of writing, there are no user-space tools available
for reading/writing to the RTC, the modified kernel sources for accessing the RTC on the
TS-7400
can be found here:
ftp://oz.embeddedarm.com/ts-arm-sbc/ts-7400-
linux/sources/rtc.c
These are byte-wide registers with the Index Register property of
write only. The Data Register has a read/write property. Valid Index Register values are
between 0 and 127, decimal. The first 14 index locations are used for accessing the RTC
Time and Date registers. The next 114 locations are non-volatile RAM locations.
4.5 Watchdog Timer
The
TS-7400
incorporates a Watchdog Timer (WDT) unit. The WDT can be used to
prevent a system “hanging” due to a software failure. The WDT causes a full system reset
when the WDT times out, allowing a guaranteed recovery time from a software error. To
prevent a WDT timeout, the application must periodically “feed” the WDT by writing a
specific value to a specific memory location.
Table: Watchdog Control Registers
Register
Address
Access
WDT Control register 0x2380_0000
Read/Write
WDT Feed register
0x23C0_0000
Write Only
The WDT Control register must be initialized with the timeout period desired. This may be
as short as 250 mS or may be as long as 8 seconds. After the WDT has been enabled,
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