ZX Interface 1
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Port | Bit | ||||||||
---|---|---|---|---|---|---|---|---|---|
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | ||
0xf7 | Read | TX Data | Net Input | ||||||
Write | Net Output / RX Data | ||||||||
0xef | Read | Busy | DTR | Gap | Sync | Write Protect | |||
Write | Wait | CTS | Erase | R/W | Comms Clock | Comms Data | |||
0xe7 | Read | Microdrive data read | |||||||
Write | Microdrive data write |
- TX Data is the value received by the serial port.
- Net Input is the value read from the Sinclair Network port.
- Bit 0 of port 0x7f is output to the serial port if Comms Data is set, or to the network port if Comms Data is reset.
- DTR signals that the remote station wishes to send data, CTS signals that the Spectrum wishes to send data
- Wait is used for network synchronisation.
- When Erase is reset the tape is erased and data is written, when set data is read.
- R/W instructs the microdrive to read or write. When R/W is set the microdrive runs, when reset it stops
- Comms Data is the value to be shifted into the microdrive select flip-flop chain.
- Comms Clock shifts the microdrive select bit along the chain.
- Write Protect is raised when a writeable cartridge is present in the selected microdrive.
- Gap and Sync are used to locate the correct block of data on the microdrive.