CS/A65 IEC

This is the parallel IEEE488 and serial IEC driver code for the fsiec OS/A65 filesystem process. It implements the hardware access with the following methods:

• IECINIT - Initialize the hardware

The following methods are used when the filesystem runs as a device (like CBM2031). This part is enclosed with the conditional variable NOLOOP. This part also handles a directory hierarchy with the CD command. This part is only available for the parallel IEEE488 interface, not the serial IEC bus.

• RETLOOP - clear the bus
• INLOOP - detect ATN activity and react as a device
• talkloop - called from INLOOP to send data (TALK)
• listenloop - called from INLOOP to receive data (LISTEN)
• sendcmd - interpret the command channel
• open - open a file

The following methods are used when the filesystem is running as bus master (similar to PET or C64). This part is enclosed with the preprocessor conditional variable NOFS.

• iec0out - send a byte with ATN set
• iecout - send a byte
• sectalk - send a secondary talk
• seclisten - send a secondary listen
• IECIN - receive a byte
• UNLISTEN - send unlisten
• UNTALK - send untalk
• getif - get interface using PSEM() and/or CTRLNMI()
• freif - release interface using VSEM() and/or CTRLNMI()

Unfortunately, due to its age, the code is a mess, but works in GeckOS/A65.

This driver handles the piezo beeper included in this board. It provides the three methods

• inibell - initialize the bell
• trigbell - trigger the bell sound
• bellirq - interrupt code that modulates the bell ring until the ring is finished. Should be called with 50Hz or the count values must be modified.