Cartridge: Difference between revisions

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Commands are 16 bytes long, and followed immediately by a 4-byte CRC-32 over the command bytes. After this, the bus ~~direction changes~~, and the bus will be 'floating' ~~for~~ a ~~few~~ cycles ('~~'TBD figure out if~~ cartridge ~~can~~ respond with ~~NAK over bad CRC during floating bus'')~~.

Commands are 16 bytes long, and followed immediately by a 4-byte CRC-32 over the command bytes. After this, the Switch stops driving the data bus, and the bus will be 'floating'. Due to the pull-ups on the bus, it will slowly converge to logic HIGH state. The Switch will clock 2 cycles to allow the bus to settle a direction change. The Switch host will then clock 2 more cycles and if the game cartridge didn't receive the CRC OK, it will respond with "00 01". Otherwise it will respond with "00 00". After this the Switch will keep clocking and the cartridge will respond with a busy signal by pulling DAT0 low.

~~Before~~ the game cartridge ~~responds with the actual response data, it will send busy bytes (LSB will be zero) to the Switch host, until it~~ is ready to send the ~~real~~ response~~. When the game cartridge is ready~~, it will ~~send~~ 2 ~~acknowledgement bytes (LSB will be one)~~ to let the Switch host know. After this, the game cartridge will send the actual response bytes.

When the game cartridge is ready to send the actual data response, it will pull the DAT0 pin high for 2 cycles to let the Switch host know. After this, the game cartridge will send the actual response bytes.

The actual response bytes are also followed immediately by a 4-byte CRC-32 over the actual response bytes.

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-Commands are 16 bytes long, and followed immediately by a 4-byte CRC-32 over the command bytes. After this, the bus direction changes, and the bus will be 'floating' for a few cycles (''TBD figure out if cartridge can respond with NAK over bad CRC during floating bus'').
+Commands are 16 bytes long, and followed immediately by a 4-byte CRC-32 over the command bytes. After this, the Switch stops driving the data bus, and the bus will be 'floating'. Due to the pull-ups on the bus, it will slowly converge to logic HIGH state. The Switch will clock 2 cycles to allow the bus to settle a direction change. The Switch host will then clock 2 more cycles and if the game cartridge didn't receive the CRC OK, it will respond with "00 01". Otherwise it will respond with "00 00". After this the Switch will keep clocking and the cartridge will respond with a busy signal by pulling DAT0 low.
-Before the game cartridge responds with the actual response data, it will send busy bytes (LSB will be zero) to the Switch host, until it is ready to send the real response. When the game cartridge is ready, it will send 2 acknowledgement bytes (LSB will be one) to let the Switch host know. After this, the game cartridge will send the actual response bytes.
+When the game cartridge is ready to send the actual data response, it will pull the DAT0 pin high for 2 cycles to let the Switch host know. After this, the game cartridge will send the actual response bytes.
 The actual response bytes are also followed immediately by a 4-byte CRC-32 over the actual response bytes.