finished DolphinDOS protocol documentation

STATUS.md

@@ -61,14 +61,22 @@ The following ROM features are currently missing:
 | VIC-II        | PARTIAL  | 80 chars in logical line support is very buggy     |
 | VDC 80 col.   | NOT DONE |                                                    |
 
-## Tape port (Tapuino, Datasette - LOAD only!)
+## Tape port (LOAD only!)
+
+* Tapuino
+* Datasette
 
 | Driver        | Status   |  Remarks                                           |
 | :-----------: | :------: | :------------------------------------------------: |
 | normal        | PARTIAL  | no error correction, no tape speed calibratrion    |
 | turbo         | PARTIAL  | up to 250 blocks, no tape speed calibratrion yet   |
 
-## IEC bus (SD2IEC, petSD+, µIEC, Pi1541, Ultimate II, most disk drives and printers, some hard drives)
+## IEC bus
+
+* SD2IEC, petSD+, µIEC
+* Pi1541, Ultimate II
+* most disk drives and printers
+* some hard drives
 
 | Driver        | Status   |  Remarks                                           |
 | :-----------: | :------: | :------------------------------------------------: |
@@ -78,13 +86,20 @@ The following ROM features are currently missing:
 | CIA burst mod | NOT DONE |                                                    |
 | Mega65 burst  | NOT DONE | pure software implementation should be feasible    |
 
-## IEEE-488 bus (petSD+, PET era disk drives and printers, various scientific equipment)
+## IEEE-488 bus
+
+* petSD+
+* PET era disk drives and printers
+* various scientific equipment
 
 | Driver        | Status   |  Remarks                                           |
 | :-----------: | :------: | :------------------------------------------------: |
 | CBM cartridge | NOT DONE |                                                    |
 
-## RS-232 (modems, parallel port printers)
+## RS-232
+
+* modems (telephone, WiFi)
+* parallel port printers
 
 | Driver        | Status   |  Remarks                                           |
 | :-----------: | :------: | :------------------------------------------------: |

doc/Protocol-DolphinDOS.md

@@ -35,7 +35,7 @@ Turnover (both to listener and to back to talker) is performed as usual.
 
 ## Sending a byte
 
-XXX TODO - not fully clear yet
+Byte transmission reuses quite some part of the standard IEC byte transmission mechanism. At the moment where EOI has been possibly signalled, controller using the standard protocol pulls CLK to indicate invalid DATA - but when DolphinDOS is in use, the C64 instead puts the byte in CIA2 port B (has to be set for output) and pulls the CLK to indicate data is now valid. Afterwards, the reader can pull DATA to indicate it's busy - everything continues the standard way.
 
 ## Receiving a byte