PDH subsystem
The Processor Dependent Hardware subsystem is the hardware that supports the PDC(firmware) in the
J Class system. There are two main parts of the PDC, the Flash PROM and Scratch RAM. Scratch RAM is
used by both the PDC and the Operating System to store run–time information. The Flash PROM
provides storage of PDC code which is the start–up code that runs the system.
The PROM consists of two 512k x 8 Flash PROMS, which are addresses sequentially, to provide 1Mbyte
of storage space for this code. Both the parts used are of AMD AM29040–120JC type. The in–circuit
programming of these parts is controlled by the U2 chip, and updates are performed by a software
“update” program which can be run off a tape drive or over the LAN.
The Scratch RAM is a 32k x 8 SRAM, PN HM62256ALFP–101. This again is controlled by the U2 chip,
and can be written to by either the firmware, or the Operating System directly.
Another part of the PDH system is the LCD. This is a 2–line x 16 display that PDC and the OS uses to
display data to the user of the system. Since there is only a power LED on the system, this display panel is
the basic vehicle to return data, messages, and error messages to the user.
Содержание Visualize J200
Страница 75: ... Figure 6 2 Package Tray Bottom View Figure 6 3 Unpacking Pictorial ...
Страница 76: ... 1 1 0 2 1 1 0 2 0 0 3 Figure 6 4 Package Pallet ...
Страница 82: ... Figure 8 1 Danish Keyboard ...
Страница 83: ... Figure 8 2 French Keyboard ...
Страница 84: ... Figure 8 3 German Keyboard ...
Страница 85: ... Figure 8 4 Italian Keyboard ...
Страница 86: ... Figure 8 5 Japanese Keyboard ...
Страница 87: ... Figure 8 6 Korean Keyboard ...
Страница 88: ... Figure 8 7 Norwegian Keyboard ...
Страница 89: ... Figure 8 8 Spanish Keyboard ...
Страница 90: ...8 10 Keyboard Layouts J Class Technical Reference Figure 8 9 Swedish Keyboard ...
Страница 91: ... Figure 8 10 Swiss Keyboard ...
Страница 92: ...8 12 Keyboard Layouts J Class Technical Reference Figure 8 11 Taiwanese Keyboard ...
Страница 93: ...8 13 J Class Technical Reference Keyboard Layouts Figure 8 12 United Kingdom Keyboard ...
Страница 94: ...8 14 Keyboard Layouts J Class Technical Reference Figure 8 13 United States Keyboard ...