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Added more coding to fbval and ZIA routing
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azonenberg committed May 21, 2017
1 parent 92bc22d commit b89ff47
Showing 1 changed file with 50 additions and 3 deletions.
53 changes: 50 additions & 3 deletions doc/xbr/notes.txt
Original file line number Diff line number Diff line change
@@ -17,7 +17,7 @@ signals on the metal 4 bus down to six. The second level is an 8:1 one-hot bitst
final routing output as either a constant value or one of the six mask mux outputs.

Mask ROM mux inputs:
Bit 5:
Bit 5 (leftmost group on M4 bus):
FB1 macrocell 15 (row 7, 12, 30, 37)
FB1 macrocell 14 (row 10, 18, 25, 38)
FB1 macrocell 13 (row 6, 13, 26)
@@ -42,8 +42,52 @@ Mask ROM mux inputs:
FB0 macrocell 11 (row 4, 14, 30, 35)
FB0 macrocell 10 (row 8, 20, 32, 34)
Bit 3:
FB0 macrocell 9 (row 3, 13, 29, 34)
FB0 macrocell 8 (row 1, 17, 32)
FB0 macrocell 7 (row 5, 20, 28, 35)
FB0 macrocell 6 (row 8, 16, 23, 36)
FB0 macrocell 5 (row 4, 21, 24, 38)
FB0 macrocell 4 (row 9, 12, 26, 33)
FB0 macrocell 3 (row 10, 14, 22)
FB0 macrocell 2 (row 2, 11, 30, 39)
FB0 macrocell 1 (row 0, 18, 27, 37)
FB0 macrocell 0 (row 6, 15, 25)
FB1 pad 15 (row 7, 19, 31)
Bit 2:
FB1 pad 14 (row )
FB1 pad 13 (row )
FB1 pad 12 (row )
FB1 pad 11 (row )
FB1 pad 10 (row )
FB1 pad 9 (row )
FB1 pad 8 (row )
FB1 pad 7 (row )
FB1 pad 6 (row )
FB1 pad 5 (row )
FB1 pad 4 (row )
Bit 1:
FB1 pad 3 (row )
FB1 pad 2 (row )
FB1 pad 1 (row )
FB1 pad 0 (row )
Dedicated input (row )
FB0 pad 15 (row )
FB0 pad 14 (row )
FB0 pad 13 (row )
FB0 pad 12 (row )
FB0 pad 11 (row )
FB0 pad 10 (row )
Bit 0 (rightmost group on M4 bus, only 10 signals vs 11):
FB0 pad 9 (row )
FB0 pad 8 (row )
FB0 pad 7 (row )
FB0 pad 6 (row )
FB0 pad 5 (row )
FB0 pad 4 (row )
FB0 pad 3 (row )
FB0 pad 2 (row )
FB0 pad 1 (row )
FB0 pad 0 (row )

Bitstream mux inputs:
Inputs are active-low except for bit 7, which is active high.
@@ -121,8 +165,11 @@ Macrocells
00 = IBUF driving ZIA
11 = unused pin
Other values unknown
13:12 "FB val" - specifies output from macrocell to the ZIA (conjecture)
Most likely one-hot to select either FF or XOR output
13:12 "FB val" - specifies output from macrocell to the ZIA
00 = unknown (not observed)
01 = unknown (not observed)
10 = flipflop feeding into ZIA
11 = ZIA output not used
11 Selects input to the flipflop
0 = input buffer
1 = XOR gate from PLA

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