6530 Programmer's Guide

Block Mode Operation
6530 Programmer’s Guide 3-81
SPACE represents a space (hex value H20), which must precede the
data.
data is the data to be written to the device when a write (40)
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 range of 00H to FFH
CR is a control character (0DH) that terminates the escape
sequence.
On all operations, except for reads, the escape sequence returns a message
with the following format:
SOH % status data terminator
where:
SOH is a control character (01H) that acts as a start of header for
messages returned to the host.
The percent 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 #,