MEA8000 Unknown Details - Revision history

LaurentFr at 15:03, 23 July 2023

2023-07-23T15:03:38Z

← Older revision		Revision as of 15:03, 23 July 2023
Line 51:		Line 51:
	== Specifications ==		== Specifications ==
	* does this doc exist in internet: "MEA8000 voice synthesizer: principles and interfacing, Philips Technical Publication 101" (Philips/Elcoma 1983)?		* does this doc exist in internet: "MEA8000 voice synthesizer: principles and interfacing, Philips Technical Publication 101" (Philips/Elcoma 1983)?
			Answer : http://zx81.ordi5.free.fr/vtr/download/MEA8000-2.pdf

MacDeath at 21:06, 17 December 2010

2010-12-17T21:06:37Z

← Older revision		Revision as of 21:06, 17 December 2010
Line 1:		Line 1:
			[[Category:Electronic Component]][[Category:Music and sound]]

	There are still a LOT of unknown details for the [[MEA8000]]. Since the chip is software programmable, it should be very easy to reverse-engineer that details - unfortunately, nobody did so, yet.		There are still a LOT of unknown details for the [[MEA8000]]. Since the chip is software programmable, it should be very easy to reverse-engineer that details - unfortunately, nobody did so, yet.

Nocash at 13:58, 23 January 2010

2010-01-23T13:58:55Z

← Older revision		Revision as of 13:58, 23 January 2010
Line 1:		Line 1:
			There are still a LOT of unknown details for the [[MEA8000]]. Since the chip is software programmable, it should be very easy to reverse-engineer that details - unfortunately, nobody did so, yet.

	== Sawtooth and/or Noise ==		== Sawtooth and/or Noise ==
	* Theoretically, the device can output only <either> sawtooth <or> noise?		* Theoretically, the device can output only <either> sawtooth <or> noise?

Nocash at 13:56, 23 January 2010

2010-01-23T13:56:40Z

← Older revision		Revision as of 13:56, 23 January 2010
Line 1:		Line 1:
	Sawtooth and/or Noise		== Sawtooth and/or Noise ==
	* Theoretically, the device can output only <either> sawtooth <or> noise?		* Theoretically, the device can output only <either> sawtooth <or> noise?
	* But, some block diagrams indicate that it can output both, added together?		* But, some block diagrams indicate that it can output both, added together?
	* Is there fade-out/fade-in switching from noise to sawtooth, or vice-versa?		* Is there fade-out/fade-in switching from noise to sawtooth, or vice-versa?

	Sample Rate (and related values)		== Sample Rate (and related values) ==
	* is sample rate (the actual sample output speed) 8000Hz or 8096Hz?		* is sample rate (the actual sample output speed) 8000Hz or 8096Hz?
	* if it is 8000Hz, then exact sample rate would be 3.84MHz/3/160?		* if it is 8000Hz, then exact sample rate would be 3.84MHz/3/160?
Line 11:		Line 11:
	* are the P and PI values in table correct (in case 8000 and 8096 are mixed)?		* are the P and PI values in table correct (in case 8000 and 8096 are mixed)?

	Filters		== Filters ==
	* is EXP formula using "-1pi" (mess emulator) or "-2pi" (datasheet)?		* is EXP formula using "-1pi" (mess emulator) or "-2pi" (datasheet)?

	Continue Mode		== Continue Mode ==
	* is repeated frame using FD=unchanged or FD=0 (=faster reactions)?		* is repeated frame using FD=unchanged or FD=0 (=faster reactions)?
	* is repeated frame using PI=unchanged (=can "run out of control")?		* is repeated frame using PI=unchanged (=can "run out of control")?

	Slow-Stop Mode		== Slow-Stop Mode ==
	* can one "resurrect" by sending data when already in "stopping" phase?		* can one "resurrect" by sending data when already in "stopping" phase?
	* does the hardware discard <incomplete> frames on slowstop?		* does the hardware discard <incomplete> frames on slowstop?
Line 24:		Line 24:
	* are FD and PI kept unchanged?		* are FD and PI kept unchanged?

	Random Generator (Noise)		== Random Generator (Noise) ==
	* works how exactly?		* works how exactly?

	Interpolations		== Interpolations ==
	* does it take the whole FD period (8..64ms) to reach new target value?		* does it take the whole FD period (8..64ms) to reach new target value?
	* - AMPL is interpolated on the translated values (eg 0.707)?		* - AMPL is interpolated on the translated values (eg 0.707)?
	* - FM/BW are interpolated on the COS/EXP values?		* - FM/BW are interpolated on the COS/EXP values?

	Status Register		== Status Register ==
	* REQ=0 occurs for 3us after 1st..3rd Frame byte (correct)?		* REQ=0 occurs for 3us after 1st..3rd Frame byte (correct)?
	* REQ=0 occurs for up to 8..64ms after 4th Frame byte (really/always)?		* REQ=0 occurs for up to 8..64ms after 4th Frame byte (really/always)?
Line 39:		Line 39:
	* is it IMPOSSIBLE to send new data during ACTIVE output (datasheet says so)?		* is it IMPOSSIBLE to send new data during ACTIVE output (datasheet says so)?

	DAC		== DAC ==
	* is there saturation occuring in case samples exceed 8bit range, and when?		* is there saturation occuring in case samples exceed 8bit range, and when?

	Clock Source		== Clock Source ==
	* can be external crystal, or external TTL, or what... an external <loop>?		* can be external crystal, or external TTL, or what... an external <loop>?

	Specifications		== Specifications ==
	* does this doc exist in internet: "MEA8000 voice synthesizer: principles and		* does this doc exist in internet: "MEA8000 voice synthesizer: principles and interfacing, Philips Technical Publication 101" (Philips/Elcoma 1983)?
	interfacing, Philips Technical Publication 101" (Philips/Elcoma 1983)?

Nocash: Created page with 'Sawtooth and/or Noise * Theoretically, the device can output only sawtooth noise? * But, some block diagrams indicate that it can output both, added together? * Is …'

2010-01-23T13:55:38Z

Created page with 'Sawtooth and/or Noise * Theoretically, the device can output only <either> sawtooth <or> noise? * But, some block diagrams indicate that it can output both, added together? * Is …'

New page

Sawtooth and/or Noise
* Theoretically, the device can output only <either> sawtooth <or> noise?
* But, some block diagrams indicate that it can output both, added together?
* Is there fade-out/fade-in switching from noise to sawtooth, or vice-versa?

Sample Rate (and related values)
* is sample rate (the actual sample output speed) 8000Hz or 8096Hz?
* if it is 8000Hz, then exact sample rate would be 3.84MHz/3/160?
* does P register overflow after 8000 or 8096 steps?
* are fm_cos and bw_exp values using divider 8000 or 8096?
* are the P and PI values in table correct (in case 8000 and 8096 are mixed)?

Filters
* is EXP formula using "-1*pi" (mess emulator) or "-2*pi" (datasheet)?

Continue Mode
* is repeated frame using FD=unchanged or FD=0 (=faster reactions)?
* is repeated frame using PI=unchanged (=can "run out of control")?

Slow-Stop Mode
* can one "resurrect" by sending data when already in "stopping" phase?
* does the hardware discard <incomplete> frames on slowstop?
* works exactly as when resending the current frame but with AMPL=0?
* are FD and PI kept unchanged?

Random Generator (Noise)
* works how exactly?

Interpolations
* does it take the whole FD period (8..64ms) to reach new target value?
* - AMPL is interpolated on the translated values (eg 0.707)?
* - FM/BW are interpolated on the COS/EXP values?

Status Register
* REQ=0 occurs for 3us after 1st..3rd Frame byte (correct)?
* REQ=0 occurs for up to 8..64ms after 4th Frame byte (really/always)?
* REQ=0 occurs for up to 8ms after Initial Pitch (really/why)?
* is it REQUIRED to send new data during ACTIVE output (to prevent slowstop)?
* is it IMPOSSIBLE to send new data during ACTIVE output (datasheet says so)?

DAC
* is there saturation occuring in case samples exceed 8bit range, and when?

Clock Source
* can be external crystal, or external TTL, or what... an external <loop>?

Specifications
* does this doc exist in internet: "MEA8000 voice synthesizer: principles and
interfacing, Philips Technical Publication 101" (Philips/Elcoma 1983)?