6530 Programmer's Guide

Conversational Mode Operation
6530 Programmer’s Guide 2-45
SPACE represents a space (H20), which must precede the data.
data is the data to be written to the device when a write (40) or
write/read (7E) operation is specified. A space must precede the data.
The data can be:
• A mode switch sequence that specifies the type of data (Esc a
for ASCII data or Esc b for binary data) to be sent on a
subsequent write.
• ASCII characters in the range of 20H to 7E.
• Binary data specified by pairs of ASCII hexadecimal pairs that
represent single characters in the specified range of 00H to
FFH.
CR is a control character (0DH) that terminates the escape sequence.
On read or write/read operations, the escape sequence returns a message
with the following format:
SOH % status data CR
where:
SOH is a control character (01H) that acts as a start of header for
messages returned to the host.
The per cent sign (%) identifies this message as an operating system
read message.
status is one of the following ASCII characters that indicates the
status of the operation:
space (20H) = operation successful
“ (22H) = file not found
$ (24H) = too many files open
% (25H) = access denied
& (26H) = invalid handle
, (2CH) = invalid access
{ (7BH) = invalid opcode
| (7CH) = invalid device
} (7DH) = device not open
~ (7EH) = invalid format