ACU Real Time Clock (DIY): Difference between revisions
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ACU Real Time Clock, DIY from magazine "Amstrad User April 85". | |||
== Technical == | |||
Uses a Z80 PIO, MM58174 RTC, 6116 (2K RAM), 32.768kHz Crystal. Both RTC and RAM are backed by rechargeable 3.6V NiCad battery. Used I/O Ports are (with only A10,A4,A3 decoded): | |||
FBE7 Z80 PIO Data In/Out Port A | |||
FBEF Z80 PIO Data In/Out Port B | |||
FBF7 Z80 PIO Configure Port A | |||
FBFF Z80 PIO Configure Port A | |||
The 4bit RTC Registers are: | |||
0 Not used | |||
1 Seconds Fraction (R) | |||
2 Seconds LSB (0..9) (R) | |||
3 Seconds MSB (0..5) (R) | |||
4 Minutes LSB (R/W) | |||
5 Minutes MSB (R/W) | |||
6 Hours LSB (R/W) | |||
7 Hours MSB (R/W) | |||
8 Day LSB (R/W) | |||
9 Day MSB (R/W) | |||
A Day of Week (R/W) | |||
B Month LSB (R/W) | |||
C Month MSB (R/W) | |||
D Leap Year Shift Register (W) | |||
E Stop/Start (W) | |||
F Interrupt (R/W) | |||
Registers 1..C are BCD (range 0..9), a value of 0Fh in these registers indicates Failure. | |||
The chip doesn't include a Year register (aside from the leap-year shift register, but it can span only 4 years, and it is write-only). | |||
== Article == | |||
<gallery> | <gallery> | ||
image:Amstrad Computer User8504 078.jpg | image:Amstrad Computer User8504 078.jpg | ||
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image:Amstrad Computer User8504 081.jpg | image:Amstrad Computer User8504 081.jpg | ||
</gallery> | </gallery> | ||
[[Category:Hardware]] [[Category:Peripherals]] [[Category:DIY]] | [[Category:Hardware]] [[Category:Peripherals]] [[Category:DIY]] | ||
Revision as of 21:19, 9 January 2010
ACU Real Time Clock, DIY from magazine "Amstrad User April 85".
Technical
Uses a Z80 PIO, MM58174 RTC, 6116 (2K RAM), 32.768kHz Crystal. Both RTC and RAM are backed by rechargeable 3.6V NiCad battery. Used I/O Ports are (with only A10,A4,A3 decoded):
FBE7 Z80 PIO Data In/Out Port A FBEF Z80 PIO Data In/Out Port B FBF7 Z80 PIO Configure Port A FBFF Z80 PIO Configure Port A
The 4bit RTC Registers are:
0 Not used 1 Seconds Fraction (R) 2 Seconds LSB (0..9) (R) 3 Seconds MSB (0..5) (R) 4 Minutes LSB (R/W) 5 Minutes MSB (R/W) 6 Hours LSB (R/W) 7 Hours MSB (R/W) 8 Day LSB (R/W) 9 Day MSB (R/W) A Day of Week (R/W) B Month LSB (R/W) C Month MSB (R/W) D Leap Year Shift Register (W) E Stop/Start (W) F Interrupt (R/W)
Registers 1..C are BCD (range 0..9), a value of 0Fh in these registers indicates Failure. The chip doesn't include a Year register (aside from the leap-year shift register, but it can span only 4 years, and it is write-only).
