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#69
Reference board User Guide for PI7C8152
By Glenn Sanders
Introduction
The Pericom PI7C8152 PCI-to-PCI bridge evaluation board demonstrates the bridge and allows testing of key
features either before or during design / layout stages. The PI7C8152 PCI Bridge complies with PCI Local Bus
specification 2.2, as well as PCI bridge specification 1.1.
Quick start
The numbers on the photo correspond to the text explanation on the right:
1
1) 3 standard, and one straddle mount PCI connectors.
2) Pin 1 on the golden PCI edge connector faces left when
looking down on the component (bridge IC socket).
3) Secondary bus Vio select : 3.3V or 5V
4) Headers for sampling signals on the primary PCI bus
5) External arbiter socket
6) Switch to set speed and misc. functions
5
3
This board comes already configured to support:
a) Primary PCI voltage (p_VIO) follows motherboard keying.
b) Secondary PCI bus voltage is set to 3.3V at J2
c) 33 MHz primary (ie primary bus M66EN is low)
d) 33 MHz secondary (ie secondary bus M66EN is low)
e) internal arbiter is enabled
f) No need to connect external power in most applications; the
host PCI bus can power all 4 secondary bus slots.
6
4
2
Default and (*) important switch settings at a glance:
SW1 there is no SW1.
SW2
signal default
1
bpcce
On
* 2
cfg66
On
3
p_M66en
On
4
s_M66en
On
* 5
PME#
Off
* 6 Arbiter_ctrl
On
7 Cntrl_GOZ
Off
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“off” Enables bus/power clock control function (BPCCE is high)
“Off” selects Bridge is 66 MHz capable.
Reference board can be used in either 66 or 33 MHz motherboard slot.
“Off” sets Secondary bus is 66 MHz capable (S_M66EN is high)
PME# is de-asserted in the off position
“On” Internal arbiter is selected
“Off” pulls SCAN_TM_L high to disable Full Scan Test Mode
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Defaults for Jumpers:
J1 not connected
J2 jumper 2-3
J3 not used
J4 jump 1-2
Normally the reference board draws all power from the motherboard
3.3 V secondary bus VIO
Ties P_VIO from motherboard PCI connector to the P_VIO signal to bridge
BEFORE POWERING THE BOARD
a) Speed selection: Using the switch SW2, choose the speed setting for the secondary bus based upon the input
primary bus speed:
SW2
33/33
66/33 secondary
66/66
Default
2-2 CONFIG66
On
Off
Not supported
Off
2-3 M66EN pri
On
Off
“
Off
2-4 M66EN sec
On
Off
“
Off
(Note: The secondary bus will have output clocks at the same frequency of the input primary clock
regardless of M66EN status at either bus.)
b) Seat the board into a PCI slot on the main system board. Looking from the front of the motherboard, the
small lip on our reference board points to the back of the motherboard and the component side with the PI7C8152
bridge chip is on the left hand side. The motherboard PCI connector is adequate to powering the board with a few
add-in cards.
c) Connect any PCI cards desired on the secondary PCI bus. For all PCI connectors on our reference board,
when looking down onto the bridge IC, pin 1 is on the left side of the board. Notice that the external arbiter socket
on the top side is closest to PCI connector pin 1. This also applies to the top mounted “straddle” connector. The
PCI slots are keyed for 3.3V or universal connector add-in cards; putting in any cards backwards will short 5V to
ground through the PCI connector. Also each PCI connector has in white stencil lettering “A1”, “B1”, “A62”, and
“B62” at the 4 corners of each slot, as a reminder where pin 1 is on each connector.
At this point, the Pericom PI7C8152 reference board is ready for you to use.
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Components and Jumper reference
U1 Pericom 8152 bridge IC
U2 not used
U3 not used
U4 not used
U5 not used
U6 PI3B3257-W Mux/Demux bus switch
U7 socket for optional external arbiter
SW1 not used
SW2 speed, options selection
J1 auxiliary power, not stuffed
J2 secondary bus Vio select
J3 +3.3V source, not stuffed
J4 primary Vio follows motherboard
TABLE
a) Right side of board has JP1, JP2, JP3 list
b) SW2 default stencil list is replaced by this
manual.
Switch listing
SW1: (does not exist)
SW2
1
signal default
bpcce
On
2
cfg66
On
3
p_M66en
On
4
s_M66en
On
5
6
PME#
Arbctrl
Off
On
7
Ctrl_GOZ#
Off
full description_______________________
“off” Enables bus/power clock control function (BPCCE is high)
“on” puts a low at this signal. (This influences turning off PCI clocks under ACPI
power management.)
“Off” selects Bridge is 66 MHz capable.
When “On” the bridge is set to 33 MHz on both primary and secondary buses.
“Off” sets P_M66EN high. Reference board can be used in 66 MHz motherboard
slot.
“Off” sets Secondary bus is 66 MHz capable (S_M66EN is high)
“On” forces 33 MHz secondary bus (S_M66EN low)
De-asserts PME# to motherboard, this switch must be “off”
“On” selects Internal arbiter; “off” selects external arbiter but other changes
needed also to activate external arbiter. See page 5.
Full Scan Test Mode. This switch must be in the “off” position for the board to
function.
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Jumper block listing
J1 external power connector. left to right [ground, ground, ground, +3.3V, +3.3V, +5V]
Not stuffed, not used. Pin 1 is +5V, pins 4-6 GND
J2 Vio select 3-2 3.3V (left)
1-2 5V
(right)
This sets Vio for the secondary bus. The PCI Bridge will drive control signals to this voltage on the secondary
bus. This should already be configured for you.
J3 3.3V pin
J3 allows a method to force the bridge to use 3.3V signaling for communicating with a 66 MHz motherboard
without disturbing the motherboard’s Vio, which is only useful when an older motherboard has a 66 MHz PCI bus
keyed for 5V. (This signal is NOT bused into the motherboard Vio.) Not stuffed.
J4 P_Vio select
The topmost pin at J4 is P_Vio from the motherboard and the center pin goes to our bridge.
Primary bus test points JP1, JP2, JP3:
These allow a logic analyzer or oscilloscope to monitor signals on the path between the 8150 and primary bus.
There are 3 rows of 16 header pins each, labeled JP1, next JP2, next JP3:
1
2
3
4
5
6
7
8
GNT
AD30
AD27
AD24
AD22
AD19
AD16
IRDY
JP1
REQ
AD29
AD26
CBE3
AD21
AD18
CBE2
TRDY
JP2
AD31
AD28
AD25
AD23
AD20
AD17
FRAME
Devsel
JP3
JP1
JP2
JP3
9
10
11
12
13
14
15
16
STOP
SERR
AD15
AD12
AD9
AD7
AD3
AD1
LOCK PAR
AD14
AD11
CBE0
AD6
AD5
AD0
PERR
CBE1
AD13
AD10
AD8
AD4
AD2
Idsel
(A copy of this table is present on the right hand side of the component side of the reference board.)
Note: correction, JP3-16 should be “IDSEL” not “Ground”
Test points description: These allow convenient sampling of signals by logic analyzer or oscilloscope:
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
T13
Primary TRST GPIO
Primary TCK GPIO
Primary TMS GPIO
INTA#
Primary TDO GPIO
(not present)
INTB#
Primary clock input
INTC#
INTD#
Primary Reset#
(not present)
SCAN_EN
TP1 ground
TP2 ground
TP3 ground
TP4 ground
TP5 ground
TP6 ground
TP7 ground
TP8 ground
TP9 Gnt to top (4th) slot
TP10 Gnt to 3rd slot
OPTIONAL External Arbiter:
For internal arbiter, SW2 -6 is ON (closed). This is the default.
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TP11
TP12
TP13
TP14
TP15
TP16
Gnt to 2nd slot
Gnt to 1st (bottom) slot
Req to top(4th) slot
Req to 3rd slot
Req to 2nd slot
Req to 1st (bottom) slot
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For external arbiter, a number of changes are made to the board:
Move SW2-6 to Off position.
Remove the 0-Ohm resistors at R35, R36, R37, R38 to remove connections from slot REQ#s to PCI
bridge. Remove R2 to disable clock connection to slot 1 (bottom most slot).
Add a rework wire from R2 pin 2 to R10 pin 1. This supplies a clock to the external arbiter.
Stuff 0-Ohm resistors into R121, R122, R123 to add REQ# connections from the external arbiter to
each slot. Also, stuff 0-Ohm resistors at R127, R128 to add GNT0# and REQ0# connections to the PCI bridge
from the External arbiter.
Finally, stuff socket U5 with an appropriately programmed Xilinx XC9572 CPLD
(availability of code TBD)
The BOTTOM slot (connector closest to PCI bridge) is not useable in external arbiter mode.
Asynchronous clock mode: This layout reference board does not have the external clock buffer and oscillator
needed for asynchronous secondary bus clock mode.
Where to find more information:
Schematics, bill of materials, gerber files, and technical assistance are all available upon request.
Or visit the company website: http://www.pericom.com/pci/psempart.php?productID=PI7C8152
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