Différences

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

--- back2root:ibm-pc-ms-dos:hardware:8253 [2023/01/14 15:59] – [Read Back Command Format (8254 only)] frater
+++ back2root:ibm-pc-ms-dos:hardware:8253 [2023/01/14 16:26] (Version actuelle) – frater
@@ Ligne 138: / Ligne 138: @@
 |  01    | select counter 1                                               |
 |  10    | select counter 2                                               |
-|  11    | read back command (8254 only, **illegal on 8253**, see below)  |
+|  11    | read back command (8254 only, **illegal on 8253**, see [[#cptread|below]])  |
-===== Read Back Command Format  (8254 only) =====
+===== Read Back Command Status (8254 only) ======
 {{anchor:cptread}}
-^  Bit  ^ Read Back Command (written to Mode Control Reg) ^
+Read from counter register
-|   0   | must be zero|
-|   1   | select counter 0|
-|   2   | select counter 1|
-|   3   | select counter 2|
-|   4   | 0 = latch status of selected counters|
-|   5   | 0 = latch count of selected counters|
-|  6-7  | 11 = read back command|
-===== Read Back Command Status (8254 only, read from counter register) ======
 ^  Bit  ^ Read Back Command Status ^

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