ubee: enable CRTC loading

Load the CRTC up for 80x25 mode using the table given in the 256TC manuals

diff --git a/Kernel/platform-ubee/ubee.s b/Kernel/platform-ubee/ubee.s
index c583575..5a13db1 100644 (file)
--- a/Kernel/platform-ubee/ubee.s
+++ b/Kernel/platform-ubee/ubee.s
@@ -82,19 +82,28 @@ to_reboot:
            out (0x50), a
            jp 0xE000
        
-;_ctc6845:                             ; registers in reverse order
-;          .db 99, 80, 85, 10, 25, 4, 24, 24, 0, 9, 101, 9, 0, 0, 0, 0
-init_early:
 ;
-;            ; load the 6845 parameters
-;          ld hl, #_ctc6845
-;          ld bc, #1588
-;ctcloop:    out (c), b                        ; register
-;          ld a, (hl)
-;          out (0x89), a               ; data
-;          inc hl
-;          djnz ctcloop
+;      This setting list comes from the Microbee 256TC documentation
+;      and is the quoted table for 80x25 mode
+;
+_ctc6845:                              ; registers in reverse order
+           .db 0x00, 0x00, 0x00, 0x20, 0x0A, 0x09, 0x0A, 0x48
+           .db 0x1a, 0x19, 0x05, 0x1B, 0x37, 0x58, 0x50, 0x6B
+
+init_early:
 
+            ; load the 6845 parameters
+           ld hl, #_ctc6845
+           ld bc, #0x100C
+ctcloop:    out (c), b                 ; register
+           ld a, (hl)
+           out (0x0D), a               ; data
+           inc hl
+           dec b
+           jr nc, ctcloop
+           ; ensure the CTC clock is right
+           xor a
+           in a, (9)                   ; manual says in but double check
            ; clear screen
            ld hl, #0xF000
            ld (hl), #'*'               ; debugging aid in top left