HP 82143A Printer Self test?

[Thomas Okken]

You should see the program perform ACCHR with 0, 1, 2, ..., 127 in the X register, ignoring the fractional part. ACCHR accumulates a single character in the printer's buffer. PRBUF is performed after every 16th character, printing the contents of the buffer and clearing it, to cause the output to be formatted in lines of 16 characters each.

In TRACE mode, you should see it print each character immediately after performing ACCHR, because in that mode, the buffer is flushed after every instruction. Running the program in MAN mode should result in the print-out looking like in my first post.

Flag 21 must be set in order for this to work, but that should be the case automatically since it is set when the calculator is turned on, as long as the 82143A is connected.