Specifications

EPC-33/34 Hardware Reference
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The ISA-bus signals are provided by the PicoPower PC/AT chipset. The buffer
strengths, Iol and Ioh, on the bus are 12mA.
The clock speed of the ISA-bus is set to approximately 8 MHz.
Terminations contained on the EPC-33/34 CPU board are as follows:
Signal Termination
Address lines
SA0 - SA19, and LA17 - LA24: 10K pullup to VCC
Data lines
SD0 - SD15: 10K pullup to VCC
Control strobes
~IOR, ~IOW, ~MEMR, ~MEMW, ~SMEMR,
~SMEMW:
4.7K pullup to VCC
Xfer response signals
~IOCS16, ~MEMCS16, ~0WS, ~MASTER: 300 ohm pullup to VCC
DRQ inputs: 10K pulldown to GND
IRQ inputs: 10K pullup to VCC
~REFRESH output: Open-collector, with 4.7K
ohm pullup to VCC
RESETDRV, OSC, BALE, AEN, SYSCLK, TC No termination
~SBHE output: 10K pullup to VCC
~IOCHCK input: 4.7K pullup to VCC
IOCHRDY input: 1K pullup to VCC
Note that pull-ups are provided on lines driven by the "current master" in order to
place these lines in a known state during the transfer of control to an ISA-bus add-in
card that uses the MASTER feature to gain control of the bus from the CPU.