Changes between Version 17 and Version 18 of geniuspc

Timestamp:

Apr 4, 2017, 7:59:46 PM (7 years ago)

Author:

pulkomandy

Comment:

--

geniuspc

@@ -63 +63 @@
 There are some things involving interrupts happening, and since the interrupt is manually vectored (jump to register), if not properly setup it will crash both the serial port and the video logic.
 To avoid problems, the serial port is kept at a low baudrate (1200 bauds) by default, and set to 9600 only when the "chat" application is running.
+
+The chat application initializes the UART by writing $C1 to address $600003 (the reset value seems to be $01).
+
+Incoming data triggers IRQ2, which the chat application sets to handle the incoming bytes into a circular buffer.
+
+{{{
+RecvSerial nop
+    move.b $600001,d3 ; Read status
+    move.b d3,d0
+    andi.l #1,d0 ; Check if Rx data available
+    moveq #1,d1
+    cmp.l d0,d1
+    bne.s RecvSerial ; If not, wait a little more
+    move.b ($600007).l,d0 ; Get the next byte of data
+    rts
+}}}
 
 == Cartridge port ==
@@ -130 +146 @@
  * $600301 Keyboard control (LEDs and stuff)
  * $600501 Video control?
- * $600600-4 Sample sound address
- * $600605 Sample sound length (0xFF = about 1 second)
+ * $600600-4 Sample sound address (big endian)
+ * $600605 Sample sound length (number of 16 bit words) (0xFF = about 1 second)
  * $600801 4 for power on, 0 for power off
- * $600901-17 Sound synthesizer (TODO)
+ * $600901 Waveshape for synth1
+ * $600903 Note for synth1
+ * $600905 Octave? for synth1
+ * $600907 Volume for Synth1
+ * $60091x Likewise for Synth2
+ * $600919 W: start playing sample / R: 1 if sample playing, 0 if finished
+
+= Acknowledgements =
+
+A lot of the contents in this page was explored by Alexandre Botzung. Many thanks to him for exploring the platform and finding nice things it is able to do.