From c7ea30dda1688ecfd44164760139b27f9536aa1b Mon Sep 17 00:00:00 2001 From: tildearrow Date: Wed, 22 Jun 2022 15:16:19 -0500 Subject: [PATCH] Revert "Revert "Added "c" in "channel" typo and added a TI-99 bit (#551)"" This reverts commit 2ffec02e26561ebaf2d0390983c7e64095473bf8. --- papers/doc/7-systems/sms.md | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/papers/doc/7-systems/sms.md b/papers/doc/7-systems/sms.md index 53560a976..882085f16 100644 --- a/papers/doc/7-systems/sms.md +++ b/papers/doc/7-systems/sms.md @@ -6,10 +6,13 @@ surely had better graphics than NES, but its sound (fairly weak, 4ch PSG with A- this console is powered by a derivative of the Texas Instruments SN76489. +the original iteration of the SN76489 used in the TI-99/4A computers was clocked much lower at 447 kHz, being able to play as low as 13.670 Hz (A -1). consequentially, pitch accuracy for higher notes is compromised. + + # effects - `20xy`: set noise mode. - - `x` controls whether to inherit frequency from hannel 3. + - `x` controls whether to inherit frequency from channel 3. - 0: use one of 3 preset frequencies (C: A-2; C#: A-3; D: A-4). - 1: use frequency of channel 3. - `y` controls whether to select noise or thin pulse.