diff --git a/constants/SP2000.inc b/constants/SP2000.inc
index 484ff89..3619822 100644
--- a/constants/SP2000.inc
+++ b/constants/SP2000.inc
@@ -1922,30 +1922,31 @@ STC3_C                  EQU     #13
 ; !TODO придумать как обозвать, чтоб было понятно когда пишут для мышки, когда для клавы и т.д.
  MODULE Z84
 ;-------------------[Ports]
+; Counter Timer Control
 CTC:
 .Ch_0                   EQU     #10       ; Control Register
 .Ch_1                   EQU     #11       ; Control Register
 .Ch_2                   EQU     #12       ; Control Register
 .Ch_3                   EQU     #13       ; Control Register
-
+; Serial I/O
 SIO:
 .Ch_A.Data              EQU     #18       ; Data register                        COM
 .Ch_A.Ctrl              EQU     #19       ; Control register                     COM
 .Ch_B.Data              EQU     #1A       ; Data register                        keyboard & mouse
 .Ch_B.Ctrl              EQU     #1B       ; Control register                     keyboard & mouse
-
+; Parallel  I/O
 PIO:
 .Port_A.Data            EQU     #1C       ; Data register                        LPT 1
 .Port_A.Command         EQU     #1D       ; Command register                     LPT 1
 .Port_B.Data            EQU     #1E       ; Data register                        LPT 2
 .Port_B.Command         EQU     #1F       ; Command register                     LPT 2
-
-WDT:                                      ; Watch-Dog timer
+; Watch Dog timer
+WDT:
 .Master_Reg             EQU     #F0       ; Master register                      WDTMR
 .Control_Reg            EQU     #F1       ; Control register                     WDTCR
-
-IntPrior_Reg            EQU     #F4       ; Interrupt Priority Register
-
+; Interrupt Priority Register
+IntPrior_Reg            EQU     #F4
+;System Control
 SYS:
 .Control                EQU     #EE       ; System Control Register Pointer      SCRP
 .Data                   EQU     #EF       ; System Control Data Port             SCDP