This update to NCIOSPEC.TXT covers the differences between the NC100 hardware
(documented in the original NCIOSPEC.TXT below) and the NC150/NC200 hardware.
This information was discovered mainly by Russell Marks during development of his
during development of my NC200 emulation for M.E.S.S.
This update does not cover the NC150. I do not have details of any differencesbetween this and the NC100 at this time.
When I have information on this system, it will be documented here.
of I/O read/writes.
- * The NC200 does not have a TC8521 Real Time Clock, instead ithas a MC146818 Real Time Clock. The MC146818 is no longer produced now,but is part of many PC designs.
- * The NC200 has a [[NEC765 ]] compatible floppy disc controller. The discinterface was designed by Ranger Computers.
The ports listed in this section are different or have additional
* The NC100 clock speed is 4.606Mhz606MHz, at this time it is unknown if the NC200has a different clock speed. * The NC100 on/off button generates an NMI.* The NC200 on/off button generates a maskable interrupt. Keyboard NC100: B0: bit 0: Shift (Left) bit 1: Shift (Right) bit 2: unused bit 3: Cursor Left (Red) bit 4: Return bit 5: unused bit 6: unused bit 7: unused B1: bit 0: Function (Yellow) bit 1: Control bit 2: Stop bit 3: Space bit 4: unused bit 5: unused bit 6: 5 bit 7: unused B2: bit 0: Caps Lock bit 1: Symbol bit 2: 1 bit 3: Tab bit 4: unused bit 5: unused bit 6: unused bit 7: unused B3: bit 0: 3 bit 1: 2 bit 2: Q bit 3: W bit 4: E bit 5: unused bit 6: S bit 7: D B4: bit 0: 4 bit 1: unused bit 2: Z bit 3: X bit 4: A bit 5: unused bit 6: R bit 7: F B5: bit 0: ?? bit 1: ?? bit 2: B bit 3: V bit 4: T bit 5: Y bit 6: G bit 7: C B6: bit 0: 6 bit 1: Cursor Down (Blue) bit 2: Del bit 3: Cursor Right (Green) bit 4: \ bit 5: / bit 6: H bit 7: N B7: bit 0: = bit 1: 7 bit 2: ~ bit 3: Up bit 4: Menu bit 5: U bit 6: M bit 7: K B8: bit 0: 8 bit 1: - bit 2: ) bit 3: ( bit 4: " bit 5: I bit 6: J bit 7: , B9: bit 0: 0 bit 1: 9 bit 2: Del bit 3: P bit 4: : bit 5: L bit 6: O bit 7: .
Address Comment R/W
======= ======= ===
00 Display Memory start W
20 Memory card wait state W
bit 7 A15 bit 6 A14 bit 5 A13 bits 4-0 Not Used
Address = 20 Write only
Memory card wait state control
bit 7: memory card wait state control: 1 for wait states, 0 for no wait bit 2: ?? bit 1: ?? bit 0: NEC765 Terminal Count input (1=TC active, 0=TC inactive) Address = 30 Write onlyFloppy motor control bit 3: Floppy motor: 1=off, 0=on
Address = 70
bit 2: Backlight: 1=off, 0=on bit 1: ?? bit 0: on/off control: 1 = on, 0 = off Address = 80centronics status bit 0: busy state
Address = A0
bit 7: memory card present 0 = yes, 1 = no bit 6: memory card write protected 1 = yes, 0 = no bit 5: lithium battery 0 if >= 2.7 volts bit 4: input voltage = 1, if >= to 4 volts bit 3: ** unknown use ** bit 2: alkaline batteries. 0 if >=3.2 volts bit 1: ** unknown use ** bit 0: battery power: if 1: batteries are too low for disk usage, if 0: batteries ok for disc usage
Address = B0 - B9 Read only
B0..B9 each key of the 64 on the keyboard
will set a bit in one of these bytes
while pressed.
bit 7: ** unknown use ** bit 6: ** unknown use ** (Real Time Clock Alarm?) bit 5: NEC765 FDC bit 4: Power off interrupt bit 3 Key scan bit 2 TC8251 Serial Interrupt (Tx Ready OR Rx Ready) bit 1 ** unknown use ** (not checked by OS - not used?) bit 0 ACK from parallel interface
Address = 80
Printer status
bit 7..1: * unknown use * bit 0: printer busy status
1 = busy
bit 7: ** unknown use ** bit 6: ** unknown use ** (Real Time Clock Alarm?) bit 5: NEC765 FDC bit 4: Power off interrupt bit 3 Key scan bit 2 TC8251 Serial Interrupt (Tx Ready OR Rx Ready) bit 1 ** unknown use ** (not checked by OS - not used?) bit 0 ACK from parallel interface
Read:
E0 = Status, E1 = data
Write:
E0 = not used, E1 = data
[http://groups.google.com/group/comp.sys.amstrad.8bit/browse_thread/thread/ce201414eff39a29/19cb6f7056d49480?lnk=gst&q=nc100+sound#19cb6f7056d49480 Russell Marks's notes about sound generation on NC100]
[[NC100 IO Specification]]
[[Category:NC Series]]