diff options
Diffstat (limited to 'src/mame/drivers/gsword.cpp')
-rw-r--r-- | src/mame/drivers/gsword.cpp | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/src/mame/drivers/gsword.cpp b/src/mame/drivers/gsword.cpp index 47398823e39..472c6a80550 100644 --- a/src/mame/drivers/gsword.cpp +++ b/src/mame/drivers/gsword.cpp @@ -153,14 +153,14 @@ So far, the AA-016 and AA-017 MCUs have been dumped successfully. At least two Great Swordsman boards have been seen with a UVEPROM-based D8741A-8 MCU for AA-013 at 9.5A. This suggests the developers made some -last-minute change to the code that only the main CPU. +last-minute change to the code that only affects the main CPU. It appears that during development, the developers worked with three copies of what became the AA-016 MCU. Protection code was added to the I/O MCU program, and this became AA-017. At this point they intended to use two copies of AA-016 for communications, and one AA-017 for I/O. It -turned out that some last-minute change was required for the master CPU, -but it was too late to order new mask ROM MUCs. This resulted in the +turned out that some last-minute change was required for the main CPU, +but it was too late to order new mask ROM MCUs. This resulted in the use of UVEPROM parts for AA-013. There are problems with sound. Many effects aren't playing or are cut @@ -255,9 +255,9 @@ contained within a single page. The initialisation/self test and mode selection, the subroutine for receiving configuration, and an unused subroutine for sending a negated program byte to the host are in page 0. The subroutines that implement coin handling are in page 1. There are -three input handling and protection programs of increasing of increasing -complexity in page 2 and page 3. The host selects the input handling -program to use with the high nybble of the first command. +three input handling and protection programs of increasing complexity in +page 2 and page 3. The host selects the input handling program to use +with the high nybble of the first command. The subroutine for receiving configuration from the host is identical to the one in the AA-016 MCU besides being shifted to a different address. @@ -310,11 +310,11 @@ command: The MCU keeps an internal credit counter ($2D). Each time the MCU receives a polling command, if the credit counter is non-zero it will be decremented and bit 7 of the response will be set; if the credit counter -is zero, but 7 of the response will be clear. +is zero, bit 7 of the response will be clear. After terminating the setup phase, any byte written to the data port will cause the MCU to check the coin inputs, update the credit counter -if necessary, and return the desired data. A byte written to the +if necessary, and return the requested data. A byte written to the control port after the setup phase terminates causes the MCU to read a byte of program memory from page 2 using the received byte as the offset, twos-complement it, return it, and then immediately re-execute |