diff options
author | Bryan Bishop <kanzure@gmail.com> | 2013-09-09 19:51:29 -0700 |
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committer | Bryan Bishop <kanzure@gmail.com> | 2013-09-09 19:51:29 -0700 |
commit | 0d6efda9bb3aa99cc9d28b9b9e7edaae121b7d75 (patch) | |
tree | e804b9ed15832481d632904f42355743d9232515 /home/handshake.asm | |
parent | 6d7043c0c65161ad8ee97fa66b94beba86761d25 (diff) | |
parent | 84a9b3907b9db08ee38e873554d8a6b4ac1b72b4 (diff) |
Merge pull request #198 from yenatch/split-predefs-specials-stds
decouple home/ from engine/
Diffstat (limited to 'home/handshake.asm')
-rw-r--r-- | home/handshake.asm | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/home/handshake.asm b/home/handshake.asm new file mode 100644 index 000000000..8ed1473e4 --- /dev/null +++ b/home/handshake.asm @@ -0,0 +1,38 @@ +AskSerial: ; 2063 +; send out a handshake while serial int is off + ld a, [$c2d4] + bit 0, a + ret z + + ld a, [$c2d5] + and a + ret nz + +; once every 6 frames + ld hl, $ca8a + inc [hl] + ld a, [hl] + cp 6 + ret c + + xor a + ld [hl], a + + ld a, $c + ld [$c2d5], a + +; handshake + ld a, $88 + ld [rSB], a + +; switch to internal clock + ld a, %00000001 + ld [rSC], a + +; start transfer + ld a, %10000001 + ld [rSC], a + + ret +; 208a + |