Delta Tau GEO BRICK LV Reference Manual

Turbo PMAC/PMAC2 Software Reference

Turbo PMAC Global I-Variables

I/O Handshake Control

Range:

0 to 3

Units:

None

Default:

I3 controls what characters, if any, are used by Turbo PMAC to delimit a transmitted line, and whether
PMAC issues an acknowledgment (handshake) of a command.

Note:

With communications checksum enabled (I4=1), checksum bytes are added after
the handshake character bytes.

Valid values of I3 and the modes they represent are:

0: Turbo PMAC does not acknowledge receipt of a valid command.  It returns a <BELL> character on
receipt of an invalid command.  Messages are sent without beginning or terminating <LF> (line feed);
simply as DATA <CR> (carriage return).

1. Turbo PMAC acknowledges receipt of a valid <CR>-terminated command with a <LF>; of an invalid

command with a <BELL> character.  Messages are sent as <LF> DATA <CR> [ <LF> DATA
<CR> ... ] <LF>.  (The final <LF> is the acknowledgment of the host command; it does not
get sent with a message initiated from a PMAC program [SEND or CMD]).  This setting is good for
communicating with dumb terminal display programs.

2. Turbo PMAC acknowledges receipt of a valid <CR>-terminated command with an <ACK>; of an

invalid command with a <BELL> character.  Messages are sent as DATA <CR> [ DATA <CR>
... ] <ACK>.  (The final <ACK> is the acknowledgment of the host command; it does not get
sent with a message initiated from a PMAC program [SEND or CMD]).  This is probably the best
setting for fast communications with a host program without terminal display.

3. Turbo PMAC acknowledges receipt of a valid <CR>-terminated command with an <ACK>; of an

invalid command with a <BELL> character.  Messages are sent as <LF> DATA <CR> [ <LF>
DATA <CR> ... ] <ACK>.  (The final <ACK> is the acknowledgment of the host command; it
does not get sent with a message initiated from a PMAC program [SEND or CMD]).

Note:

I3 does not affect how DPRAM ASCII communications are performed.

Examples:
With I3=0:

#1J+<CR> ........

; Valid command not requiring data response

..........................

; No acknowledging character

UUU<CR> ..........

; Invalid command

<BELL> .............

; PMAC reports error

P1..3<CR> ......

; Valid command requiring data response

25<CR>50<CR>75<CR>

; PMAC responds with requested data

With I3=1: