//
// Official Kernal routine, described in:
//
// - [RG64] C64 Programmer's Reference Guide   - page 303
// - [CM64] Compute's Mapping the Commodore 64 - page 224
// - https://www.pagetable.com/?p=1031, , https://github.com/mist64/cbmbus_doc
// - http://www.zimmers.net/anonftp/pub/cbm/programming/serial-bus.pdf
//
// CPU registers that has to be preserved (see [RG64]): .X, .Y
//


UNLSN:

	// According to serial-bus.pdf (page 15) this routine flushes the IEC out buffer
	jsr iec_tx_flush

	// Buffer empty, send the command
	lda #$3F

	jmp common_open_close_unlsn_second