Ziatech Corporation ZT 8907, Hardware User Manual

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1. Introduction
ÛZIATECH
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DMA
The ZT 8907's two DMA controllers provide a total of four DMA channels for data
transfers between STD bus I/O and local memory. The DMA channels support STD bus
DMA slaves by managing the data transfers between the slaves and local memory.
Additional features of the DMA channels include auto initialization, address increment or
decrement, and software DMA requests.
DMA channel 2, is an 8-bit channel available on the backplane through STD bus
BUSRQ* and BUSAK*. Channel 2 is primarily used for floppy disk expansion. Three
additional DMA channels are available through a 10-pin frontplane connector (J6).
Each of the three frontplane DMA channels can be independently configured for 8-bit or
16-bit operation. These are designated as DMA0/5, DMA1/6 and DMA 3/7. DMA
channels 0, 1 and 3 are 8-bit channels. DMA channels 5, 6 and 7 are 16-bit DMA
channels. See Chapter 6, "
DMA Controller ," for more information.
Watchdog Timer
The watchdog timer optionally monitors system operation. If the watchdog timer is
enabled it must be strobed at least every 500 ms. Failure to strobe the watchdog timer
within this time period will result in a system reset. See Chapter 12, "
Watchdog Timer ,"
for more information.
Real-Time Clock
The real-time clock performs timekeeping functions and includes 128 bytes of battery-
backed CMOS RAM. Timekeeping features include an alarm function, a maskable
periodic interrupt, and a 100-year calendar. See Chapter 7, "
Real-Time Clock ," and
Chapter 16, " Memory Module Socket (U17) ," for more information.
Keyboard Controller
The ZT 8907 includes a PC/AT
®
keyboard controller that operates when a zPM PCI bus
video adapter is installed (in connectors J11 and J13). The keyboard and VGA video
signals are available at connector J7. An optional cable is available through Ziatech.
Parallel Printer Port Interface
The ZT 8907 includes a PC/AT printer interface for connection to a Centronics™-
compatible printer. The printer interface is available through a 20-pin frontplane
connector (J9). An optional cable is available from Ziatech to interface the frontplane
connector to a standard 25-pin female D connector. For more information, see
Chapter 9, "
Parallel Port Printer Interface ."