Curiosity got the best of me again. :blink: Couldn't find info on these three signals:
52 SBO~. . . . . . . . . .
54 SDONE . . . . . . . .
58 STOP~. . . . . . . . .
They're all n.c. on the serial modem card's pinout so they're on the PCI side of things, but I couldn't find a clear equivalent in PCI signal listings. Info on the rest is from:
http://www.interfacebus.com/Design_PCI_Pinout.html which I checked against the DevNote - PowerMac 5500-6500.pdf
49 SERR~. . . . . . . . . [Open Drain] System Error is for reporting address parity errors, data parity errors on the
Special Cycle command, or any other system error.
50 PAR . . . . . . . . . . [Tri-state] Parity is even parity across AD[31::00] and C/BE[3::0]#. Parity generation is required by all PCI agents.
PAR is stable and valid one clock after each address phase.
51 PERR~. . . . . . . . . [Sustained Tri-State] Parity Error is only for the reporting of data parity errors. Two Parity lines are made available,
one for the 32 bit bus width (bits 0 to 31) and an additional one for the 64 bit expansion (bits 32 to 63).
Two error bits; I assume, 1 for the LSB 32 bits and one for the upper 32 bits.
53 LOCK~. . . . . . . . [Sustained Tri-State] Lock indicates an atomic operation to a bridge that may require multiple transactions to complete.
When LOCK# is asserted, non-exclusive transactions may proceed to a bridge that is not currently locked.
57 DEVSEL~. . . . . . . [Sustained Tri-State] Device Select, when actively driven, indicates the driving device has
decoded its address as the target of the current access.
59 IRDY~. . . . . . . . . [Sustained Tri-State] Initiator Ready indicates the initiating agent's (bus master's) ability to complete the
current data phase of the transaction. IRDY# is used in conjunction with TRDY#.
60 TRDY~. . . . . . . . . [Sustained Tri-State] Target Ready indicates the target agent's (selected device's) ability to complete the
current data phase of the transaction. TRDY# is used in conjunction with IRDY#.
64 FRAME~. . . . . . . . [Sustained Tri-State] Cycle Frame is driven by the current master to indicate the beginning and duration of an access.
36 C/BE(0)~
45 C/BE(1)~
63 C/BE(2)~
77 C/BE(3)~ . . . . . . . [Tri-state] Bus Command and Byte Enables are multiplexed on the same PCI pins.
During the address phase of a transaction, C/BE[3::0]# define the bus command.
78 IDSEL. . . . . . . . . . [input] Initialization Device Select is used as a chip select during configuration read and write transactions.
91 REQ~. . . . . . . . . . [Tri-state] Request indicates to the arbiter that this agent desires use of the bus.
This is a point-to-point signal. Every master has its own REQ# line.
92 GNT~. . . . . . . . . . GNT# [Tri-state] Grant indicates to the agent that access to the bus has been granted.
The GNT line is a point-to-point signal, each master has its own GNT# signal.
95 INT~. . . . . . . . . . . [Open Drain] Interrupts on PCI are optional and are "level sensitive," asserted low (negative true). --- INTA#, INTB#, INTC#, INTD#
98 RST~. . . . . . . . . . [input] Reset; used to bring registers and signals to a known state
101 CLK. . . . . . . . . . . Clock; rising edge provides timing for all transactions
32-bit Address/Data Bus: Time Multiplexed on PCI Bus, The DevNote doesn't have signal definitions.
23 A1 24 A0
25 A3 26 A2
29 A5 30 A4
31 A7 32 A6
35 A8 37 A10
38 A9 41 A12
42 A11 43 A14
44 A13 46 A15
65 A17 66 A16
69 A19 70 A18
71 A21 72 A20
72 A23 74 A22
79 A25 80 A24
81 A27 82 A26
85 A29 86 A28
87 A31 88 A30
These are on the modem pinout along with a lot of sound and microphone oriented junk.
1 /DCD . . . . . . . . . . Modem
2 /DTR . . . . . . . . . . Modem
3 /CTS . . . . . . . . . . Modem
4 /RTS. . . . . . . . . . . Modem
5 RxD. . . . . . . . . . . . Modem
6 TxD. . . . . . . . . . . . Modem
7 IN_SENSE. . . . . . . Modem
8 SCC_ENAB. . . . . . Modem
I'm wondering if anything at all needs to be jumpered from CS2 for adding a third PCI slot? I've got a three slot riser that works in my Beige G3 board, looks like it's time to test it in one of the 6500 boards? Dunno, whatcha think, trag?