TI Synthesizer Update

In the March 1984 issue of COMPUTE!, reader Jim Pate suggested using CALL PEEK(–28672, SP) on the TI-99/4A to check if the Speech Synthesizer is attached. He said that if it were attached, SP would be 96. This was correct to an extent. Because the address –28672 is part of the speech read/write buffer, sometimes (like after a CALL SPGET or CALL SAY) a value of 96 will not be placed into SP. To avoid this problem, instead of:

IF SP = 96 THEN CALL SAY ("UHOH")

use this:

IF SP THEN CALL SAY ("UHOH")

This way, the CALL SAY statement will execute as long as SP is not 0.

Mark Chance

Thank you for the clarification on this.