Différences

Ci-dessous, les différences entre deux révisions de la page.

--- back2root:ibm-pc-ms-dos:hardware:8042 [2022/12/29 16:43] – [8042 Commands Related to PC Systems (Port 64h)] frater
+++ back2root:ibm-pc-ms-dos:hardware:8042 [2023/01/05 03:12] (Version actuelle) – [Keyboard Responses to System (read port 60h)] frater
@@ Ligne 54: / Ligne 54: @@
-<WRAP rounded box>
+<WRAP round box>
 command F7h through FDh are NOP's on the AT and are ACK'ed but not acted upon
 </WRAP>
@@ Ligne 60: / Ligne 60: @@
 see [[back2root:ibm-pc-ms-dos:hardware:8042|8042]],  MAKE CODES,  BREAK CODES,  INT 16,3
-===== 8042 - Speaker Controller (AT,PS/2) - Port 61h =====
+===== 8042 - Speaker Controller & NMI (AT,PS/2) - Port 61h =====
+This register can be Write and Read
+^  bit  ^ Description                                                          ^
+|  0    | PIT Channel 2 enabled (see [[back2root:ibm-pc-ms-dos:hardware:8253|8253]])   |
+|  1    | Speaker Position\\ <tab>1 : "out" position\\ <tab>0 : "in" position  |
+|  2    |                                                                      |
+|  3    |                                                                      |
+|  4    |                                                                      |
+|  5    |                                                                      |
+|  6    |                                                                      |
+|  7    | Reset Keyboard status (scan code readed)                             |
+=== Speaker ===
 The speaker itself has two possible positions, "in" and "out".
-This position can be set through bit 1 of port 0x61 on the Keyboard Controller. If this bit is set (=1), the speaker will move to the "out" position, if it is cleared (=0) then the speaker will move to the "in" position. Moving in and out repeatedly produces audible tones if the speed of repetition (the frequency) is within the range the speaker can reproduce and the human ear can hear. Also, a single movement in or out makes a click sound because it's so fast. Thus, a frequency which is too low to be heard as a tone may be heard as a rattle or buzz. (In fact, any frequency produced by this system also produces higher frequencies; look up "square wave harmonics" if you're interested.)
+This position can be set through bit 1 of port 0x61 on the Keyboard Controller.
+If this bit is set (=1), the speaker will move to the "out" position, if it is cleared (=0) then the speaker will move to the "in" position.
+Moving in and out repeatedly produces audible tones if the speed of repetition (the frequency) is within the range the speaker can reproduce and the human ear can hear. Also, a single movement in or out makes a click sound because it's so fast. Thus, a frequency which is too low to be heard as a tone may be heard as a rattle or buzz. (In fact, any frequency produced by this system also produces higher frequencies; look up "square wave harmonics" if you're interested.)
 ==== 8042 Status Register (port 64h read) ====

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