Nintendo 1504166 Programming Manual - Page 22
Game Pak RAM Wait Control, PHI Terminal Output Control
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AGB Programming Manual AGB Memory If the Prefetch Buffer Flag is disabled, the fetch is done from the Game Pak ROM. There is a wait based on the wait state associated with the fetch instruction to the Game Pak ROM in respect to the CPU. WAITCNT [d12 - 11] PHI Terminal Output Control Controls the output from the PHI terminal. This should always be set to 00(No Output). WAITCNT [d10 - 08],[d07 - 05],[d04 - 02] Wait State Wait Control Individual wait cycles for each of the three areas(Wait States 0-2) that occur in Game Pak ROM can be set. The relation between the wait control settings and wait cycles is as follows. Use the appropriate settings for the device you are using. Wait Control Value 000 001 010 011 100 101 110 111 1st Access 4 3 2 8 4 3 2 8 Wait Cycles 2nd Access Wait State Wait State 0 1 2 4 2 4 2 4 2 4 1 1 1 1 1 1 1 1 Wait State 2 8 8 8 8 1 1 1 1 After executing the System ROM (when the User Program is started) the Wait Control Value is 000. In the Game Pak Mask ROM used with the actual manufactured product, the specifications are 1st Access/3 Wait, 2nd Access/1 Wait. In this case, set the Wait Control Value to 101. WAITCNT [d01 - 00] Game Pak RAM Wait Control Wait cycles for the Game Pak RAM can be set. The relation between the wait control settings and wait cycles is as follows. Use the appropriate settings for the device you are using. Wait Control Value 00 01 10 11 Wait Cycles 4 3 2 8 ©1999 - 2001 Nintendo of America Inc. 22 D.C.N. AGB-06-0001-002B4