Differences

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--- memory_map [2021/09/05 18:02] – [External bus configuration] simer
+++ memory_map [2021/09/05 18:12] – [Misc. peripherals] simer
@@ Line 6: / Line 6: @@
 | 0x003000  |	0x0037FF  |	[[Sound]]   |
 | 0x003D00  |	0x003DFF  |	[[IO]]      |
-| 0x003e00  |	0x003E03  |	[[memory_map#General DMA|DMA]]     |
+| 0x003E00  |	0x003E03  |	[[memory_map#General DMA|DMA]]     |
 External memory starts at 0x4000. It can be mapped to the internal ROM and the two possible chips in the cartridges.
@@ Line 90: / Line 90: @@
 | 3D1C	  | Scanline counter         |
-Timebase values:
+Timebase setup values:
+  * Bits 3-2: TMB2 frequency
-  - 00: TMB2 = 128Hz, TMB1 = 8Hz
+    * 00 - 128 Hz
-  - 01: TMB2 = 256Hz, TMB1 = 16Hz
+    * 01 - 256 Hz
-  - 10: TMB2 = 512Hz, TMB1 = 32Hz
+    * 10 - 512 Hz
-  - 11: TMB2 = 1024Hz, TMB1 = 64Hz
+    * 11 - 1024 Hz
+  * Bits 1-0: TMB1 frequency
+    * 00 - 8 Hz
+    * 01 - 16 Hz
+    * 10 - 32 Hz
+    * 11 - 64 Hz
 ===== Timer A =====
@@ Line 155: / Line 160: @@
 | 3D2D	  | Pseudo Random2	                   |
 | 3D2E	  | FIQ Sel				   |
-| 3D2F    | DS register                            |
+| 3D2F    | DS register (sets or gets data segment value of CPU status register) |
 ===== System control =====