
TS-7250 MANUAL
HARDWARE COMPONENTS
The TS-NVRAM peripheral board is located at the PC/104 memory space base address of
0x11AA_0000. This resource is a byte-wide memory device using a lithium battery that is
guaranteed to last a minimum of 10 years with or without power applied.
On-Board NAND Flash
The
TS-7250
uses a NAND Flash chip for its on-board Flash resource. The physical
address of the Flash chip is
0x6000_0000
. The first 16KB is reserved for the TS-
BOOTROM code. The TS-BOOTROM code initializes various internal configuration
registers for proper operation, and initializes and tests the SDRAM. The last 3 MB are
reserved for the RedBoot ROM monitor, RedBoot FIS (Flash Image System) and RedBoot
FCONFIG (Flash configuration).
The Linux kernel shipped by default is pre-loaded in the FIS and the default boot script
and Ethernet MAC address are contained in the FCONFIG. You may also use the
RedBoot FIS to store and load images that contain eCos applications or other OS/RTOS
boot loaders.
The rest of the on-board flash is used for the Linux YAFFS2 file system. This is a
journaling file system that is aware of the wear-out mechanism of the NAND flash and
incorporates ECC algorithms at the file system level to maximize Flash lifetime. It is also
extremely tolerant of power failures during file write sequences.
The entire Flash chip can be write-protected by removing Jumper 3. When JP3 is not
installed, the Flash chip becomes a read-only resource.
Note
It is possible to use larger sizes of the NAND Flash than the standard 32 MB chip.
The
TS-7250
is designed to accommodate both 32 MB and 128 MB chips,
providing up to 256 MB of on-board flash. Contact Technologic Systems for larger
Flash sizes.
Note
The YAFFS1 file system runs on the
TS-7250
boards that feature NAND chips
with 512 byte page size, enabling up to 128 MB of on-board flash. The YAFFS2
file system supports the new NAND technology, with 2k page size, hence it will be
installed on
TS-7250
boards that are configured with 128-256 MB of flash.
USB Flash Drive or Compact Flash Card
Additional non-volatile storage may be added with a USB flash drive or a Compact Flash
card. These devices supply additional non-volatile storage either for data or for a complete
operation system distribution, such as Debian. A tar-file of Debian is available on the
Technologic Systems website. Alternatively, the developer's kit includes a USB flash
thumb-drive or Compact Flash card pre-loaded with Debian.
Flash memory provided by these devices behaves much as a hard drive does with sizes
ranging from 32MB to 1GB. These products are inherently more rugged than a hard drive
since they are completely solid-state with no moving parts. However, they have the added
advantage of being removable media
Use of a Compact Flash card with TS-7250 SBC or higher requires a USB Compact flash
adapter, which will also be included in the TS-ARM Development Kit if requested. The
USB flash drive has the advantage over a CF card in that the USB drive can be hot
swapped.
© Jan, 2010 www.embeddedARM.com 17