Delta Tau PMAC
==============

Notation: "$" denotes hexadecimal number.

Configuring PMAC
----------------

- Set the "VMEbus Address Modifier" (I90):
	- $39 for A24 non privileged data access (default).
	- $3D for A24 supervisory data access.
	- $9  for A32 non privileged data access.
	- $D  for A32 supervisory data access.

- Enable both "supervisory" and "non-privileged" VMEbus data access by setting
	the "VMEbus Address Modifier Don't Care Bits" (I91) to $4 (default).

- For A32 addressing only, set the "VME Base Address Bits A31-A24" (I92) to the
	two most significant hex nibbles; e.g. for $A123 0000 set I92 to $A1.
	The default value ($FF) is N/A.

- Set the "VME Mailbox Address Bits A23-A16" (I93) so it does not conflict with
	the DPRAM (default value - $7F).
	
- Set the "VME Mailbox Address Bits A15-A08" (I94) so it does not conflict with
	the DPRAM (default value - $A0).

- Set the "VME DPRAM Base Address Bits A23-A20" (I97); for example,
	- for A32 addressing, at base address $A123 0000 set I97 to $23.
	- for A24 addressing, at base address $00D0 0000 set I97 to $D0.
	The default value is $0.

- Set the "VME DPRAM Enable" (I98) to $E0 to enable DPRAM access; the default
	value is $60.
	
- Set the "VME Address Width Control" (I99) to:
	- $90 for A24 addressing.
	- $80 for A32 addressing.
	The default value is $30.

- Enable DPRAM ASCII communication; set I58 to 1.

- Download "Suggested M-variable definitions".  In particular, this device driver
	uses;
	- M0161->D:$088
	- M0162->D:$08B
	- M0261->D:$108
	- M0262->D:$10B
	...	...
	- M3261->D:$1008
	- M3262->D:$100B
	
