HS-82C55ARH Ver la hoja de datos (PDF) - Intersil
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HS-82C55ARH Datasheet PDF : 17 Pages
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HS-82C55ARH
STB
TSLSH
IBF
TSLIH
INTR
TSHNH
RD
INPUT FROM
PERIPHERAL
TPVSH
TRLNL
TRHIL
TSHPX
FIGURE 16. MODE 1 (STROBED INPUT)
Output Control Signal Definition
OBF (Output Buffer Full F/F)
The OBF output will go “low” to indicate that the CPU has
written data out to the specified port. This does not mean
valid data is sent out of the port at this time since OBF can
go true before data is available. Data is guaranteed valid at
the rising edge of OBF. See Note 1. The OBF F/F will be set
by the rising edge of the WR input and reset by ACK input
being low.
ACK (Acknowledge Input)
A “low” on this input informs the HS-82C55ARH that the data
from Port A or Port B is ready to be accepted. In essence, a
response from the peripheral device indicating that it is
ready to accept data. See Note 14.
INTR (Interrupt Request)
A “high” on this output can be used to interrupt the CPU
when an output device has accepted data transmitted by the
CPU. INTR is set by the rising edge of ACK and reset by the
falling edge of WR.
MODE 1 (PORT A)
CONTROL WORD
D7 D6 D5 D4 D3 D2 D1 D0
1 0 1 0 1/0
PC4, 5
1 = INPUT
0 = OUTPUT
MODE 1 (PORT B)
CONTROL WORD
D7 D6 D5 D4 D3 D2 D1 D0
1
10
PA7 - PA0 8
PB7 - PB0 8
PC7
OBF
PC1
A
INTE PC6
A
ACK
A
INTE PC2
B
WR
WR
PC3
INTR
PC0
A
2
PC4, 5
I/O
OBF
B
ACK
B
INTR
B
FIGURE 17. MODE 1 OUTPUT
INTE A
Controlled by Bit Set/Reset of PC6.
INTE B
Controlled by Bit Set/Reset of PC2.
WR
OBF
TWHOL
TKHOL
INTR
TWLNL
ACK
OUTPUT
TWHPV
TKLKH
TKHNH
FIGURE 18. MODE 1 (STROBED OUTPUT)
NOTE:
14. To strobe data into the peripheral device, the user must operate
the strobe line in a hand shaking mode. The user needs to send
OBF to the peripheral device, generate an ACK from the
peripheral device and then latch data into the peripheral device
on the rising edge of OBF.
Combinations of Mode 1: Port A and Port B can be
individually defined as input or output in Mode 1 to support a
wide variety of strobed I/O applications.
PORT A (STROBED INPUT)
PORT B (STROBED OUTPUT)
CONTROL WORD
D7 D6 D5 D4 D3 D2 D1 D0
1 0 1 1 1/0 1 0
PC6, 7
1 = INPUT
0 = OUTPUT
PORT A (STROBED OUTPUT)
PORT B (STROBED INPUT)
CONTROL WORD
D7 D6 D5 D4 D3 D2 D1 D0
1 0 1 0 1/0 1 1
PC4, 5
1 = INPUT
0 = OUTPUT
RD PA7 - PA0 8
PC4
STB A
PC5
PC3
2
PC6, 7
IBF A
INTR A
I/O
WR PB7 - PB0 8
PC1
OBF B
PC2
ACK B
PC0
INTR B
WR PA7 - PA0 8
PC7
OBF A
PC6
PC3
2
PC4, 5
ACK A
INTR A
I/O
RD PB7 - PB0 8
PC2
STB B
PC1
IBF B
PC0
INTR B
FIGURE 19. COMBINATIONS OF MODE 1
13
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