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author AJR <ajrhacker@users.noreply.github.com>2019-05-18 17:14:00 -0400
committer AJR <ajrhacker@users.noreply.github.com>2019-05-18 17:14:00 -0400
commit52f299f6160e3027e91ba4710d50d4e1efab8ed0 (patch)
treea27f1b7c9fa4ab2e6b8902b024f3f0a3b1dfb184
parent0c887cc30f4207ea2691842781423cebca0df77b (diff)
atari810, atari1050: Add notes on format; correct mirroring (nw)
-rw-r--r--src/devices/bus/a800/atari1050.cpp12
-rw-r--r--src/devices/bus/a800/atari810.cpp8
2 files changed, 19 insertions, 1 deletions
diff --git a/src/devices/bus/a800/atari1050.cpp b/src/devices/bus/a800/atari1050.cpp
index b3ed498bba3..12191d4cc72 100644
--- a/src/devices/bus/a800/atari1050.cpp
+++ b/src/devices/bus/a800/atari1050.cpp
@@ -4,6 +4,16 @@
Atari 1050 Dual Density Disk Drive
+ This SIO peripheral device controls one 5¼" floppy disk drive. Two
+ soft-sectored data formats are supported:
+ * Single density: FM, 40 tracks, 18 sectors/track (88K bytes)
+ * Double density: MFM, 40 tracks, 26 sectors/track (133K bytes;
+ requires DOS3)
+
+ As with the 810, the 1050 uses parallel port outputs to operate the
+ drive mechanism's four-phase stepper motor at 288 RPM. The FDC's own
+ stepping outputs are not used, and its index pulse is synthesized.
+
***************************************************************************/
#include "emu.h"
@@ -37,7 +47,7 @@ void atari1050_device::mem_map(address_map &map)
map(0x0000, 0x007f).mirror(0x0900).ram(); // MCM6810
map(0x0080, 0x00ff).mirror(0x0900).m(m_pia, FUNC(mos6532_new_device::ram_map));
map(0x0280, 0x029f).mirror(0x0960).m(m_pia, FUNC(mos6532_new_device::io_map));
- map(0x0400, 0x0403).mirror(0x087c).rw(m_fdc, FUNC(wd2793_device::read), FUNC(wd2793_device::write));
+ map(0x0400, 0x0403).mirror(0x0bfc).rw(m_fdc, FUNC(wd2793_device::read), FUNC(wd2793_device::write));
map(0x1000, 0x1fff).rom().region("rom", 0);
}
diff --git a/src/devices/bus/a800/atari810.cpp b/src/devices/bus/a800/atari810.cpp
index 6967d641753..69b5bd09d2f 100644
--- a/src/devices/bus/a800/atari810.cpp
+++ b/src/devices/bus/a800/atari810.cpp
@@ -4,6 +4,14 @@
Atari 810 Disk Drive
+ The 810 is the original 5¼" floppy disk interface for the Atari 400/800
+ computer, supporting only a 709-sector single density format.
+
+ The built-in drive mechanism uses a four-phase stepper motor which is
+ controlled by outputs to a PIA port rather than by the WD1771-01 FDC.
+ The PIA also generates a synthetic index pulse for the FDC. (The format
+ defines the undersized 19th sector of each track as the index area.)
+
***************************************************************************/
#include "emu.h"