Help ‘‘This selects the arbitration level and DMA channel for Channel 1 Receiver.’’
NamedItem
Prompt ‘DMA Arbitration Level for Channel 1 Receiver’
choice ‘Level 0‘
pos
[
2
]4
0000XXXXb
arb 0
choice ‘Level 1‘
pos
[
2
]4
0001XXXXb
arb 1
choice ‘Level 3‘
pos
[
2
]4
0011XXXXb
arb 3
choice ‘Level 4‘
pos
[
2
]4
0100XXXXb
arb 4
choice ‘Level 5‘
pos
[
2
]4
0101XXXXb
arb 5
choice ‘Level 6‘
pos
[
2
]4
0110XXXXb
arb 6
Help ‘‘This selects the arbitration level and DMA channel for Channel 2 Receiver.’’
NamedItem
Prompt ‘DMA Arbitration Level for Channel 1 Transmitter‘
choice ‘Level 0‘
pos
[
3
]4
XXXX0000b
arb 0
choice ‘Level 1‘
pos
[
3
]4
XXXX0001b
arb 1
choice ‘Level 3‘
pos
[
3
]4
XXXX0011b
arb 3
choice ‘Level 4‘
pos
[
3
]4
XXXX0100b
arb 4
choice ‘Level 5‘
pos
[
3
]4
XXXX0101b
arb 5
choice ‘Level 6‘
pos
[
3
]4
XXXX0110b
arb 6
Help ‘‘This selects the arbitration level and DMA channel for Channel 1 Transmitter.’’
PC16552C Adapter PAL/State Machine Equations
BUSARB:
Local Arbiter State Machine
The following asynchronous state machine controls the Local Arbiter on the Adapter Card. The device used is a 20L8 PAL.
outputs: q3, q2, q1, q0, burst, preout, ack, enarb: pins 21, 20, 19, 18, 17, 16, 22, 15;
inputs: dreq, arbgnt, buswin, prein, chrst: pins 1, 2, 3, 4, 5;
States of Arbiter
idle
e
[
1,1,1,1
]
;
req
e
[
1,1,1,0
]
; ‘‘req uchannel bus; preout (q0) active
arb
e
[
1,0,1,0
]
; ‘‘vector enabled; preout, enarb active
lose
e
[
1,0,0,0
]
; ‘‘lost arb battle; preout active
xfer1
e
[
0,0,1,0
]
; ‘‘intermediate state to xfer2
xfer2
e
[
0,0,1,1
]
; ‘‘xfering data on bus; burst ack active
xfer3
e
[
1,0,1,1
]
; ‘‘intermediate state to idle
Equations
!q0
e
idle & !dreq & !larbgnt & !chrst
#
‘‘This is also PREEMPT
req & !dreq & !arbgnt & !chrst
Ý
req & !dreq & arbgnt & !chrst
Ý
arb & arbgnt & !chrst
Ý
arb & !arbgnt & buswin & !chrst
Ý
arb & !arbgnt & !buswin & !chrst
Ý
lose & !arbgnt & !chrst
Ý
lose & arbgnt & !chrst;
!q1
e
arb & !arbgnt & buswin & !chrst
Ý
lose & !arbgnt & !chrst;
!q2
e
req & !dreq & arbgnt & !chrst
Ý
arb & arbgnt & !chrst
Ý
arb & !arbgnt & buswin & !chrst
Ý
arb & !arbgnt & !buswin & !chrst
Ý
lose & !arbgnt & !chrst
Ý
lose & arbgnt & !chrst
Ý
xfer1 & !chrst
Ý
xfer2 & !dreq & !arbgnt & !chrst
Ý
xfer2 & dreq & !arbgnt & !chrst;
15
Summary of Contents for PC16552C
Page 2: ...PC16552C Adapter Block Diagram TL F 11195 1 2 ...
Page 18: ...TL F 11195 7 18 ...
Page 19: ...TL F 11195 8 19 ...
Page 20: ...TL F 11195 9 20 ...
Page 21: ...TL F 11195 10 21 ...
Page 22: ...TL F 11195 11 22 ...
Page 23: ...TL F 11195 12 23 ...