Delta Tau GEO BRICK LV User Manual

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Turbo PMAC User Manual 
398 
Writing a Host Communications Program 
• 
ASCII Command and Response Buffers 
• 
Data Gathering Buffer 
• 
Background Variable Copying Buffers 
• 
Binary Rotary Program Download 
Physical Configuration and Connection 
On the Turbo PMAC-PC, the dual-ported RAM option is a separate ½-slot board that connects to the 
Turbo PMAC’s CPU board with 2 short ribbon cables, and has its own ISA bus connector.  On other 
board-level Turbo PMACs, the dual-ported RAM is an on-board option in which the DPRAM IC is 
installed directly on the PMAC. 
The UMAC Turbo’s CPU board has DPRAM as an on-board option to support the PC/104 port that may 
be present.  The Acc-54E USB/Ethernet board for the UMAC Turbo comes standard with its own 
DPRAM IC that interfaces to the CPU board through the UBUS backplane.  USB or Ethernet 
communications through the Acc-54E will use this DPRAM IC; it cannot use the DPRAM IC on the CPU 
board itself. 
The UMAC Turbo’s new integrated CPU and high-speed communications board has integrated USB and 
Ethernet communications functionality.  The optional on-board DPRAM supports these ports. 
The UMAC-CPCI’s CPU board has integrated USB and Ethernet communications functionality.  The 
optional on-board DPRAM supports these ports.  The (planned) “bridge” board to link the UMAC-CPCI 
CPU board to a CPCI backplane has its own DPRAM IC for CPCI-port communications. 
The QMAC control board has optional on-board DPRAM to support USB and Ethernet communications. 
Host Address Setup 
The dual-ported RAM has a fixed address space in the Turbo PMAC’s address space.  However, its 
address space in the host computer can vary depending on the setup of the card.  The specification of the 
address of the card in the host computer is done entirely in software; there are no jumpers or DIP-switches 
to set. 
ISA Bus Setup 
There are two setup variables in the Turbo PMAC for the addressing of the DPRAM on the ISA bus in 
the PC’s memory space: I93 and I94.  (Note that the standard “host” bus communications port is mapped 
into the PC’s I/O space, and has no relationship to the DPRAM memory address.)  Because the PC uses 
byte addressing, a 16k x 8 slot of memory space must be found or created in the PC for the 8k x 16 
DPRAM.  For the 32k x 16 DPRAM, either a 64k x 8 slot of memory space must be found, or a 16k x 8 
slot found and “bank” addressing used. 
Note that the PC/104 bus is completely software-compatible with the ISA bus, so these instructions apply 
to setting up DPRAM on the PC/104 interface of the 3U Turbo PMAC (Turbo Stack or UMAC Turbo). 
Typically in a PC, a slot of memory space between 640k ($0A0000) and 1M ($100000), where no 
standard memory resides, is used.  Other devices also may occupy regions of this space.  VGA displays 
often occupy the space from 640k to 704k ($0A0000 to $0B0000) and the BIOS often occupies from 
960k to 1M ($0F0000 to $100000).   
Locating the DPRAM between 1M ($100000) and 16M ($FFFFFF) is possible, but most operating 
systems cannot tolerate a break in their normal RAM addressing, so the DPRAM must be placed after the 
end of regular RAM.  Since most PCs now have more than 16M of RAM, usually this is not feasible. 
Therefore, in most PCs, the DPRAM is located somewhere between 704k ($0B0000) and 960k 
($0F0000).  The default settings locate it in the range from $0D4000 through $0D7FFF.