Use the PSG - Revision history

1BitFeverDreams: /* Examples: */ formatting, paragraphs

2025-08-24T13:24:02Z

Examples:: formatting, paragraphs

← Older revision		Revision as of 09:24, 24 August 2025
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	<p>These examples focus on PSG1, so send these bytes to address 0xD600 (left PSG)		<p>These examples focus on PSG1, so send these bytes to address 0xD600 (left PSG)

	0b1001 0100 : Attenuation command that targets PSG1, Tone 1 to set a middle volume. This can be used as a "note on" event if you had set the frequency prior to this.<br>		<p>0b1001 0100 Attenuation command that targets PSG1, Tone 1 to set a middle volume. This can be used as a "note on" event if you had set the frequency prior to this.<br>
	0b1000 1101 Frequency setting command part 1, that targets PSG1, Tone 1. This sends the first lower 4 bits of information based on a transformed 440 Hz<br>		0b1000 1101 Frequency setting command part 1, that targets PSG1, Tone 1. This sends the first lower 4 bits of information based on a transformed 440 Hz<br>
	0b0000 1111 Frequency setting command part 2, that targets PSG1, Tone 1. This sends the final higher 6 bits of information based on a transformed 440 Hz		0b0000 1111 Frequency setting command part 2, that targets PSG1, Tone 1. This sends the final higher 6 bits of information based on a transformed 440 Hz<br>
			0b1001 1111 Attenuation command that targets PSG1, Tone 1 to completely turn off its volume. This can be used as a "note off" event<br>

	~~0b1001 1111 Attenuation command that targets PSG1~~, Tone 1 to ~~completely turn off its volume. This can be used as a "note off" event~~		<p>These examples focus on PSG2, Tone 2, so send these bytes to address 0xD610 (right PSG)

	~~These examples focus on PSG2, Tone 2, so send these bytes to address 0xD610 (right PSG)~~		<p>0b1011 0100 Attenuation command that targets PSG2, Tone 2 to set a middle volume. This can be used as a "note on" event if you had set the frequency prior to this.<br>

	0b1011 0100 : Attenuation command that targets PSG2, Tone 2 to set a middle volume. This can be used as a "note on" event if you had set the frequency prior to this.<br>
	0b1010 1001 Frequency setting command part 1, that targets PSG2, Tone 2. This sends the first lower 4 bits of information based on a transformed 208 Hz G#<br>		0b1010 1001 Frequency setting command part 1, that targets PSG2, Tone 2. This sends the first lower 4 bits of information based on a transformed 208 Hz G#<br>
	0b0010 0001 Frequency setting command part 2, that targets PSG2, Tone 2. This sends the final higher 6 bits of information based on a transformed 208 Hz G#		0b0010 0001 Frequency setting command part 2, that targets PSG2, Tone 2. This sends the final higher 6 bits of information based on a transformed 208 Hz G#<br>
			0b1011 1111 Attenuation command that targets PSG2, Tone 2 to completely turn off its volume. This can be used as a "note off" event<br>
	0b1011 1111 Attenuation command that targets PSG2, Tone 2 to completely turn off its volume. This can be used as a "note off" event

	=== Frequency bytes in arrays meant for the C language, hard coded ===		=== Frequency bytes in arrays meant for the C language, hard coded ===

1BitFeverDreams: more examples and frequency formula explained

2025-08-24T13:21:43Z

more examples and frequency formula explained

@@ Line 139: / Line 139: @@
 |-
 |}
-<p>0b1001 0100 (middle volume "attenuation" command)<br>
+=== How to use the master formula with frequencies ===
-b1000 1101 (low byte of the note)<br>
+To get to the PSG clock, you start with a 315 000 000 Hz reference divided by 22, yielding 14,318,181.81... (81 repeating) called the [[wikipedia:Crystal_oscillatir_frequencies|14.31818 MHz NTSC M color subcarrier]]. Then, you divided it again by 4, yielding 3,579,545 Hz as the PSG master clock..
-<p>to stop the sound, send to 0xD600:
+To generate the values needed for the PSG register, follow this procedure:
-<p>0b1001 1111 (max attenuation closes off the sound)
+) divide the PSG master clock of 3,579,545 Hz by 32, and then also divide that by the frequency in Hz of the note. n = psg_master_clock / (32 * f) where n is the number destined for the registers and f is the frequency in Hz.
 === Frequency bytes in arrays meant for the C language, hard coded ===

1BitFeverDreams: typos

2025-02-16T05:05:27Z

typos

← Older revision		Revision as of 01:05, 16 February 2025
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	==== Command with Low frequency bits, table for tone 1 (the high nybble will be set to A): ====		==== Command with Low frequency bits, table for tone 2 (the high nybble will be set to A): ====

	uint8_t psgLow[] = {		uint8_t psgLow[] = {
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	0xAd,0xAc,0xAa};		0xAd,0xAc,0xAa};

	==== Command with Low frequency bits, table for tone 1 (the high nybble will be set to C): ====		==== Command with Low frequency bits, table for tone 3 (the high nybble will be set to C): ====

	uint8_t psgLow[] = {		uint8_t psgLow[] = {

1BitFeverDreams: more details on the commands to send, more pre-calculated tables for all 3 tones now

2025-02-16T04:40:57Z

more details on the commands to send, more pre-calculated tables for all 3 tones now

Show changes

1BitFeverDreams: /* Frequency bytes in C, meant for tone 1 */ formatting

2024-12-18T06:38:54Z

Frequency bytes in C, meant for tone 1: formatting

← Older revision		Revision as of 02:38, 18 December 2024
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	uint8_t psgLow[] = {		uint8_t psgLow[] = {

	0x86,		0x86,
	0x8d,0x87,0x84,0x84,0x87,0x8d,0x84,0x8e,0x8b,0x89,0x89,0x8b,		0x8d,0x87,0x84,0x84,0x87,0x8d,0x84,0x8e,0x8b,0x89,0x89,
	0x8e,0x83,0x8a,0x82,0x8b,0x86,0x82,0x8f,0x8d,0x8c,0x8c,0x8d,
	0x8f,0x81,0x85,0x89,0x8d,0x83,0x89,0x8f,0x86,0x8e,0x86,0x8e,		0x8b,
	0x87,0x80,0x8a,0x84,0x8e,0x89,0x84,0x8f,0x8b,0x87,0x83,0x8f,		0x8e,0x83,0x8a,0x82,0x8b,0x86,0x82,0x8f,0x8d,0x8c,0x8c,
	0x8b,0x88,0x85,0x82,0x8f,0x8c,0x8a,0x87,0x85,0x83,0x81,0x8f,
			0x8d,
			0x8f,0x81,0x85,0x89,0x8d,0x83,0x89,0x8f,0x86,0x8e,0x86,

			0x8e,
			0x87,0x80,0x8a,0x84,0x8e,0x89,0x84,0x8f,0x8b,0x87,0x83,

			0x8f,
			0x8b,0x88,0x85,0x82,0x8f,0x8c,0x8a,0x87,0x85,0x83,0x81,

			0x8f,
	0x8d,0x8c,0x8a};		0x8d,0x8c,0x8a};


	uint8_t psgHigh[] = {		uint8_t psgHigh[] = {

	0x3f,		0x3f,
	0x3b,0x38,0x35,0x32,0x2f,0x2c,0x2a,0x27,0x25,0x23,0x21,0x1f,		0x3b,0x38,0x35,0x32,0x2f,0x2c,0x2a,0x27,0x25,0x23,0x21,
	0x1d,0x1c,0x1a,0x19,0x17,0x16,0x15,0x13,0x12,0x11,0x10,0xf,
	0xe,0xe,0xd,0xc,0xb,0xb,0xa,0x9,0x9,0x8,0x8,0x7,		0x1f,
	0x7,0x7,0x6,0x6,0x5,0x5,0x5,0x4,0x4,0x4,0x4,0x3,		0x1d,0x1c,0x1a,0x19,0x17,0x16,0x15,0x13,0x12,0x11,0x10,
	0x3,0x3,0x3,0x3,0x2,0x2,0x2,0x2,0x2,0x2,0x2,0x1,
			0xf,
			0xe,0xe,0xd,0xc,0xb,0xb,0xa,0x9,0x9,0x8,0x8,

			0x7,
			0x7,0x7,0x6,0x6,0x5,0x5,0x5,0x4,0x4,0x4,0x4,

			0x3,
			0x3,0x3,0x3,0x3,0x2,0x2,0x2,0x2,0x2,0x2,0x2,

			0x1,
	0x1,0x1,0x1};		0x1,0x1,0x1};

1BitFeverDreams: added my computed values in C

2024-12-18T06:37:15Z

added my computed values in C

← Older revision		Revision as of 02:37, 18 December 2024
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	<p>0b1001 1111 (max attenuation closes off the sound)		<p>0b1001 1111 (max attenuation closes off the sound)

			=== Frequency bytes in C, meant for tone 1 ===
			The high nybble of the low byte is set at 8 for tone 1,
			replace with A for tone 2, or with C for tone 3

			uint8_t psgLow[] = {
			0x86,
			0x8d,0x87,0x84,0x84,0x87,0x8d,0x84,0x8e,0x8b,0x89,0x89,0x8b,
			0x8e,0x83,0x8a,0x82,0x8b,0x86,0x82,0x8f,0x8d,0x8c,0x8c,0x8d,
			0x8f,0x81,0x85,0x89,0x8d,0x83,0x89,0x8f,0x86,0x8e,0x86,0x8e,
			0x87,0x80,0x8a,0x84,0x8e,0x89,0x84,0x8f,0x8b,0x87,0x83,0x8f,
			0x8b,0x88,0x85,0x82,0x8f,0x8c,0x8a,0x87,0x85,0x83,0x81,0x8f,
			0x8d,0x8c,0x8a};
			uint8_t psgHigh[] = {
			0x3f,
			0x3b,0x38,0x35,0x32,0x2f,0x2c,0x2a,0x27,0x25,0x23,0x21,0x1f,
			0x1d,0x1c,0x1a,0x19,0x17,0x16,0x15,0x13,0x12,0x11,0x10,0xf,
			0xe,0xe,0xd,0xc,0xb,0xb,0xa,0x9,0x9,0x8,0x8,0x7,
			0x7,0x7,0x6,0x6,0x5,0x5,0x5,0x4,0x4,0x4,0x4,0x3,
			0x3,0x3,0x3,0x3,0x2,0x2,0x2,0x2,0x2,0x2,0x2,0x1,
			0x1,0x1,0x1};

1BitFeverDreams: /* The PSG is inside the FPGA of the F256Jr, F256K, F256Jr2 and F256K2 */ formatting

2024-12-18T06:32:09Z

The PSG is inside the FPGA of the F256Jr, F256K, F256Jr2 and F256K2: formatting

← Older revision		Revision as of 02:32, 18 December 2024
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	Example:		Example:
	To produce a 440 Hz A on Tone 1, send these bytes to address 0xD600 (left PSG)		<p>To produce a 440 Hz A on Tone 1, send these bytes to address 0xD600 (left PSG)
	~~0b1001 0100 (middle volume "attenuation" command)~~
	~~0b1000 1101 (low byte of the note)~~
	~~0b0000 1111 (high byte of the note~~)

	to stop the sound, send to 0xD600:		<p>0b1001 0100 (middle volume "attenuation" command)<br>
	0b1001 1111 (max attenuation closes off the sound)		0b1000 1101 (low byte of the note)<br>
			0b0000 1111 (high byte of the note).

			<p>to stop the sound, send to 0xD600:

			<p>0b1001 1111 (max attenuation closes off the sound)

1BitFeverDreams: start of the guide to use the PSG

2024-12-18T06:30:12Z

start of the guide to use the PSG

New page

== The PSG is inside the FPGA of the F256Jr, F256K, F256Jr2 and F256K2 ==

The F256 machines have a dual PSG based on the SN76489 inside the Beatrix FPGA which generate 3 tones of square wave
and one noise generator each.<br>

{| class="wikitable"
|+
!Register Name
!Address
!Description
|-
|PSG_LEFT
|0xD600
|Send all formatted commands here to the left PSG
|-
|PSG_RIGHT
|0xD610
|Send all formatted commands here to the right PSG
|-
|PSG_COMBINED_LEFT_RIGHT
|0xD608
|Send all formatted commands here to both PSG
|-
|SYS1
|0xD6A1
|System Ctrl reg: bit2 sets PSG_ST = psg status. if 0, left and right are mixed to monaural output. if 1, left and right are normal stereo
|}

=== Command Formats ===

Example:
To produce a 440 Hz A on Tone 1, send these bytes to address 0xD600 (left PSG)
0b1001 0100 (middle volume "attenuation" command)
0b1000 1101 (low byte of the note)
0b0000 1111 (high byte of the note)

to stop the sound, send to 0xD600:
0b1001 1111 (max attenuation closes off the sound)