User's Manual

PMAC Dual-Ported RAM User Manual
4 Dual-Ported RAM Communications
Example:
To configure the DPRAM to start at $EC000 in PC memory. There is 8K of DPRAM and 24-bit
addressing is needed. To configure and enable the DPRAM, either use the PMAC Executive program’s
dual-port RAM configuration feature or send the following commands directly to PMAC.
WX:$786,$0000E,$000C5 ;configure DPRAM for $EC000
save ;save configuration to EAROM
$$$ ;re-initialize the card
The last hex digit 5 comes from the above binary number 0101 = $5
Unused
24-bit Addr.
8K RAM
Enabled
To disable the DPRAM, you could use the PMAC Executive program’s dual-port RAM configuration
feature or send the following commands directly to PMAC.
WX:$786,$0000E,$000C4 ;disable DPRAM
save ;save configuration to EAROM
$$$ ;re-initialize the card
Default values
in PMAC
PROM
Reset with Re-initialize
(E51 ON
or $$$***)
Non-volatile
Storage Registers
in PMAC
EEPROM
SAVE
Normal
Reset
User Interface
Registers in
PMAC RAM
(VME) RHX$783,10
(PC) RHX$786,2
WX$783, ... (VME)
WX$786, ... (PC)
Any Reset
Active Interface
Control Registers
Setup
Computer
Normal Setup Procedure
1. Send values from setup computer
to PMAC User interface registers
2. SAVE values to PMAC EEPROM
3. Reset PMAC to copy values
into active control registers
VME and/or DPRAM Address Setup
PMAC
Setting up the VME Dual-Ported RAM (Option 2V)
There is no hardware setup or connections for the Option 2V DPRAM on the PMAC VME or PMAC2-
VME. It is factory installed on the PMAC board itself.
Starting Address
Before you can communicate with PMAC VME through the DPRAM, you must setup its starting address.
Initial communications to the VME for setup of the address of the VME mailbox registers is done over the
serial port. The setup of the DPRAM address can be done either with or after the mailbox setup (see
Writing a Host Communications Program in the PMAC User Manual).