Maple Systems OIT Family (ASCII) User Manual

Page 35

The OIT notifies the ASCII host with the Notify Host of R/W Register Update command:

ESC

X memarea memaddr length data

STX

mem area = C or D (register bank)

mem addr = 0000 to 1023 (The address is in decimal, base 10, format and must be

four digits. For example, 0010, not 10.)

length =

1 means the OIT wrote one bit

2 means the OIT wrote one byte

3 means the OIT wrote two bytes

4 means the OIT wrote four bytes

data =

The data the OIT wrote to the register. The number of bytes varies

(max. 8). Leading zeroes are used so that the number of digits is

always the same for each format (for example, even if the length is 3,

the number of digits is always four).

if length = 1, then data is either 0 or 1

if length = 2, then data is from 00 to FF

if length = 3, then data is from 0000 to FFFF

if length = 4, then data is from 00000000 to FFFFFFFF

The OIT does not expect any response back from the ASCII host when it sends this com-

mand. In Interactive mode, the OIT sends the line terminator in addition to the command ter-

minator with each command. In Network mode, the OIT does not send the Notify Host of

R/W Register Update command immediately. Instead, the command is stored in the OIT’s

polling buffer where it resides until the Poll Buffer control command is sent by the ASCII

host. A line terminator is appended to the contents of the polling buffer rather than to the end

of each command.

Register Monitor Formats

To correctly monitor a data value in an OIT register, the OIT programmer must select the

proper register monitor format for each register monitor used. The register monitor format

determines if the OIT sees the OIT register data value as a signed number, hexadecimal or

BCD number, 16-bit or 32-bit number, etc.

Signed: This format is used to represent a 16-bit register in the OIT as a signed integer value

with a range of -32,768 to +32,767.

Decimal: This format is used to represent a 16-bit register in the OIT as an unsigned integer

value with a range of 0 to 65,535.

OIT Family Operation Manual (ASCII)

1010-0088, REV02

MESSAGE ALARM

RUN