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--- documentations:devices:thmfc1 [2014/03/25 21:40] – created pulkomandy
+++ documentations:devices:thmfc1 [2015/02/28 18:08] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
-The THMFC1 is a custom floppy controller developped by Thomson and used in the TO8, TO9+, and TO8D, as well as the floppy controller expansion for the MO6 (which also works on older machines). It's a very flexible floppy controller, as it leaves a big part of the work to the CPU. One interesting fact is the ability to use QDD drives as well as regular floppies.
+The THMFC1 is a custom floppy controller developed by Thomson and used in the TO8, TO9+, and TO8D, as well as the floppy controller expansion for the MO6 (which also works on older machines). It's a very flexible floppy controller, as it leaves a big part of the work to the CPU. One interesting fact is the ability to use QDD drives as well as regular floppies.
 ====== Register map ======
@@ Line 12: / Line 12: @@
 |E7D7   |WCELL      |cell size adjust|
+<columns>
+===== E7D0: CMD0 =====
+^Bit^Description^
+|7  |Must be 0      |
+|6  |Must be 0      |
+|5  |MFM (0)/ FM (1)|
+|4  |Enable sync detection |
+|3  |Disable sync detection (format track) |
+|2  |Write enable                          |
+|1,0|Operation code |
+Operations:
+  * 00: reset
+  * 01: write sector
+  * 10: read address
+  * 11: read sector
+<newcolumn>
+===== E7D1: CMD1 =====
+^Bit^Description   ^
+|7  |Compatibility |
+|6,5|Sector length |
+|4  |Side select   |
+|3-1|Timing compensation |
+|0  |Enable READY signal detection|
+Sector sizes:
+  * 00: 128 bytes
+  * 01: 256 bytes
+  * 10: 512 bytes
+  * 11: 1024 bytes
+Timing compensation:
+  * 62.5ns steps, must be set to 437.5ns
+<newcolumn>
+===== E7D2: CMD2 =====
+^Bit^Description^
+|6  |Side select|
+|5  |Step direction (0 = towards track 0)|
+|4  |Step|
+|2  |Motor on|
+|1  |Drive select 1|
+|0  |Drive select 0|
+</columns>
+===== E7D0: STAT0 =====
+^Bit^Description^
+|7  |Character clock image (?)|
+|6,5|Must be 0|
+|4  |Operation finishing|
+|3  |Operation finished |
+|2  |CRC error |
+|1  |Similar to bit 7, for automated operations|
+|0  |Sync detection |
+===== E7D1: STAT1 =====
+^Bit^Description^
+|7  |Must be 0|
+|6  |Index pulse detection|
+|5  |Disk change          |
+|4  |Motor state (1=stopped)|
+|3  |Track 0                |
+|2  |Write protected        |
+|1  |Ready                  |
+===== E7D4: clock type =====
+Must be set to FF when writing data bytes, or 0A when writing synchronization bytes (inter-sector gaps). Other values may be used for custom disk formatting, at your own risk.
+===== E7D7: WCELL =====
+  * Bit 7: set to 0 for inner tracks of disk. Compensate writes for the smaller disk surface.
+  * Bit 6: ?
+====== Sector format ======
+The controller uses the standard shugart MFM coding for sectors, but can be programmed to do other things as well.
+|      ^Byte count^Contents    ^Description    ^
+^Header|12        |00          |Bit synchronization |
+^:::   |3         |A1 clock 0A |Char synchronization|
+^:::   |1         |FE          |Header mark         |
+^:::   |1         |            |Track id            |
+^:::   |1         |            |Side id             |
+^:::   |1         |            |Sector id           |
+^:::   |1         |            |Sector size         |
+^:::   |2         |            |CRC check           |
+^:::   |22        |            |Header GAP          |
+^Data  |12        |00          |Bit synchronization |
+^:::   |3         |A1 clock 0A |Char synchronization|
+^:::   |1         |FE          |Data mark           |
+^:::   |sector length|         |Data                |
+^:::   |2         |            |CRC check           |
+^:::   |variable  |            |Data GAP            |