UPI-41AH Datasheet, PDF (5/20 Pages) Intel Corporation – UNIVERSAL PERIPHERAL INTERFACE 8-BIT SLAVE MICROCONTROLLER

5 P₂₆ and P₂₇ are port pins or DMA handshake pins
for use with a DMA controller These pins default
to port pins on Reset
If the ‘‘EN DMA’’ instruction has been executed
P₂₆ becomes the DRQ (DMA Request) pin A ‘‘1’’
written to P₂₆ causes a DMA request (DRQ is acti-
vated) DRQ is deactivated by DACKRD
DACKWR or execution of the ‘‘EN DMA’’ in-
struction
If ‘‘EN DMA’’ has been executed P₂₇ becomes
the DACK (DMA ACKnowledge) pin This pin acts
as a chip select input for the Data Bus Buffer reg-
isters during DMA transfers
UPI-41AH 42AH
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Figure 5 8088-UPI-41AH 42AH Interface
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DMA Handshake Capability
EN DMA Op Code 0E5H
1 110010 1
D₇
D₀
6 When EA is enabled on the UPI the program
counter is placed on Port 1 and the lower three
bits of Port 2 (MSB ^e P₂₂ LSB ^e P₁₀) On the
UPI this information is multiplexed with PORT
DATA (see port timing diagrams at end of this
data sheet)
7 The 8741AH and 8742AH support the inteligent
Programming Algorithm (See the Programming
Section )
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Figure 6 8048H-UPI-41 42 Interface
APPLICATIONS
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Figure 7 UPI-41 42-8243 Keyboard Scanner
Figure 4 UPI-41AH 42AH Keyboard Controller
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