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White Electronic Designs

WED3C7558M-XBX

August 2002
Rev. 7

FEATURES

Footprint compatible with WED3C750A8M-200BX

Footprint compatible with Motorola MPC 745

RISC Microprocessor Multichip Package

OVERVIEW

The WEDC 755/SSRAM multichip package is targeted for
high performance, space sensitive, low power systems and
supports the following power management features: doze,
nap, sleep and dynamic power management.

The WED3C7558M-XBX multichip package consists of:

755 RISC processor

Dedicated 1MB SSRAM L2 cache, confi gured as
128Kx72

21mmx25mm, 255 Ceramic Ball Grid Array (CBGA)

Core Frequency/L2 Cache Frequency (300MHz/
150MHz, 350MHz/175MHz)

Maximum 60x Bus frequency = 66MHz

The WED3C7558M-XBX is offered in Commercial (0°C
to +70°C), industrial (-40°C to +85°C) and military (-55°C
to +125°C) temperature ranges and is well suited for
embedded applications such as missiles, aerospace,
fl ight computers, fi re control systems and rugged critical
systems.

* This product is subject to change without notice.

FIGURE 1 MULTI-CHIP PACKAGE DIAGRAM

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White Electronic Designs

WED3C7558M-XBX

August 2002
Rev. 7

PACKAGE PINOUT LISTING

Signal Name

Pin Number

Active

I/O

2.0V (7)

3.3V (7)

A[0-31]

C16, E4, D13, F2, D14, G1, D15, E2, D16, D4, E13, G2, E15, H1, E16, H2, F13, J1,
F14, J2, F15, H3, F16, F4, G13, K1, G15, K2, H16, M1, J15, P1

High

I/O

AACK#

Low

Input

ABB#

Low

I/O

AP[0-3]

C1, B4, B3, B2

High

I/O

ARTRY#

Low

I/O

A10

2.0V

BG#

Low

Input

BR#

Low

Output

BVSEL (4, 5, 6)

High

Input

GND

3.3V

CI#

Low

Output

CKSTP_IN#

Low

Input

CKSTP_OUT#

Low

Ouput

CLK_OUT

Output

DBB#

J14

Low

I/O

DBG#

Low

Input

DBDIS#

H15

Low

Input

DBWO#

Low

Input

DH[0-31]

P14, T16, R15, T15, R13, R12, P11, N11, R11, T12, T11, R10, P9, N9, T10, R9, T9,
P8, N8, R8, T8, N7, R7, T7, P6, N6, R6, T6, R5, N5, T5, T4

High

I/O

DL[0-31]

K13, K15, K16, L16, L15, L13, L14, M16, M15, M13, N16, N15, N13, N14, P16,
P15, R16, R14, T14, N10, P13, N12, T13, P3, N3, N4, R3, T1, T2, P4, T3, R4

High

I/O

DP[0-7]

M2, L3, N2, L4, R1, P2, M4, R2

High

I/O

DRTRY#

G16

Low

Input

GBL#

Low

I/O

GND

C5, C12, E3, E6, E8, E9, E11, E14, F5, F7, F10, F12, G6, G8, G9, G11, H5, H7,
H10, H12, J5, J7, J10, J12, K6, K8, K9, K11, L5, L7, L10, L12, M3, M6, M8, M9,
M11, M14, P5, P12

GND

HRESET#

Low

Input

INT#

B15

Low

Input

L1_TSTCLK (1)

D11

High

Input

L2_TSTCLK (1)

D12

High

Input

L2AV

(8)

L11

2.0V

L2OV

(9)

E10, E12, M12, G12, G14, K12, K14

2.0V

3.3V

L2VSEL (4, 5, 6, 7)

High

Input

*--

3.3V

LSSD_MODE# (1)

B10

Low

Input

MCP#

C13

Low

Input

NC (No-connect)

C3, C6, D5, D6, H4, A4, A5, A2, A3

(2)

C7, E5, G3, G5, K3, K5, P7, P10, E7, M5, M7, M10

PLL_CFG[0-3]

A8, B9, A9, D9

High

Input

QACK#

Low

Input

QREQ#

Low

Output

RSRV#

Low

Output

SMI#

A16

Low

Input

SRESET#

B14

Low

Input

STCK (10)

Input

STDI

Input

STDO

J16

Output

* Not supported on this version

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White Electronic Designs

WED3C7558M-XBX

August 2002
Rev. 7

PACKAGE PINOUT LISTING (continued)

Signal Name

Pin Number

Active

I/O

2.0V (7)

3.3V (7)

STMS

Input

SYSCLK

Input

TA#

H14

Low

Input

TBEN

High

Input

TBST#

A14

Low

I/O

TCK

C11

High

Input

TDI (6)

A11

High

Input

TDO

A12

High

Output

TEA#

H13

Low

Input

TLBISYNC#

Low

Input

TMS (6)

B11

High

Input

TRST# (6)

C10

Low

Input

TS#

J13

Low

I/O

TSIZ[0-2]

A13, D10, B12

High

Output

TT[0-4]

B13, A15, B16, C14, C15

High

I/O

Low

Output

(2)

F6, F8, F9, F11, G7, G10, H6, H8, H9, H11, J6, J8, J9, J11, K7, K10, L6, L8, L9

2.0V

VOLDET (3)

Low

Output

NOTES:
1.

These are test signals for factory use only and must be pulled up to OV

for

normal machine operation.

2. OV

inputs supply power to the I/O drivers and V

inputs supply power to the

processor core.

Internally tied to GND in the BGA package to indicate to the power supply that a
low-voltage processor is present. This signal is not a power supply pin.

To allow processor bus I/0 voltage changes, provide the option to connect BVSEL
and L2VSEL independently to either OV

(Selects 3.3V Interface) or to GND

(Selects 2.0V Interface).

Uses one of 15 existing no-connects in WEDC's WED3C750A8M-200BX.

6. Internal pull up on die.
7. OV

supplies power to the processor bus, JTAG, and all control signals except

the L2 cache controls (L2CE, L2WE, and L2ZZ); L2OV

supplies power to the L2

cache I/O interface (L2ADDR (0-16], L2DATA (0-63), L2DP{0-7] and L2SYNC-OUT)
and the L2 control signals and the SSRAM power supplies; and V

supplies power

to the processor core and the PLL and DLL (after fi ltering to become AV

and

L2AV

respectively). These columns serve as a reference for the nominal voltage

supported on a given signal as selected by the BVSEL/L2VSEL pin confi gurations
and the voltage supplied. For actual recommended value of Vin or supply voltages
see Recommended Operating Conditions.

Uses one of 20 existing V

pins in WEDC's WED3C750A8M-200BX, no board

level design changes are necessary. For new designs of WED3C7558M-XBX refer
to PLL power supply fi ltering.

9. L20V

for future designs that will require 2.0V L2 cache power supply - compatible

with existing design using WED3C750A8M-200BX.

10. To disable SSRAM TAP controllers without interfering with the normal operation of

the devices, STCK should be tied low (GND) to prevent clocking the devices.

11. STDI and STMS are internally pulled up and may be left unconnected. Upon

power-up the SSRAM devices will come up in a reset state which will not interfere
with the operation of the device.

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White Electronic Designs

WED3C7558M-XBX

August 2002
Rev. 7

RECOMMENDED OPERATING CONDITIONS

Characteristic

Symbol

Recommended Value

Unit

Core supply voltage

2.0 ± 100mV

PLL supply voltage

2.0 ± 100mV

L2 DLL supply voltage

L2AV

2.0 ± 100mV

Processor bus supply voltage

BVSEL = 0

2.0 ± 100mV

BVSEL = 1

3.3 ± 165mV

L2 bus supply voltage

L2VSEL = 1

L20V

3.3 ± 165mV

Input Voltage

Processor bus

GND to OV

JTAG Signals

GND to OV

NOTE: These are the recommended and tested operating conditions. Proper device operation outside of these conditions is not guaranteed.

ABSOLUTE MAXIMUM RATINGS

Characteristic

Symbol

Value

Unit

Notes

Core supply voltage

-0.3 to 2.5

(4)

PLL supply voltage

-0.3 to 2.5

(4)

L2 DLL supply voltage

L2AV

-0.3 to 2.5

(4)

60x bus supply voltage

-0.3 to 3.465

(3)

L2 bus supply voltage

L2OV

-0.3 to 3.465

(3)

Input supply

Processor Bus

-0.3 to 0V

+0.3

(2)

L2 bus

-0.3 to L20V

+0.3

(2)

JTAG Signals

-0.3 to 3.6

(2)

Storage temperature range

STG

-55 to 150

°C

NOTES:
1.

Functional and tested operating conditions are given in Operating Conditions table. Absolute maximum ratings are stress ratings only, and functional operation at the maximums is
not guaranteed. Stresses beyond those listed may affect device reliability or cause permanent damage to the device.

Caution: Vin must not exceed OV

by more than 0.3V at any time including during power-on reset.

Caution: OV

/L2OV

must not exceed V

/AV

/L2AV

by more than 1.6 V at any time including during power-on reset.

Caution: V

/AV

/L2AV

must not exceed L2OV

/OV

by more than 0.4 V at any time including during power-on reset.

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White Electronic Designs

WED3C7558M-XBX

August 2002
Rev. 7

POWER CONSUMPTION

= AV

= 2.0 ± 0.1V Vdc, OV

= 3.3V ± 5% Vdc, GND = 0 Vdc, 0 T

< 105°C

Processor (CPU) Frequency/L2 Frequency

Unit

Notes

300/150 MHz

350/175MHz

Full-on Mode

Typical

4.1

4.6

1, 3

Maximum

6.7

7.9

1, 2

Doze Mode

Maximum

2.5

2.8

1, 2

Nap Mode

Maximum

1700

1800

1, 2

Sleep Mode

Maximum

1200

1300

1, 2

Sleep ModePLL and DLL Disabled

Maximum

500

1, 2

NOTES:
1.

These values apply for all valid 60x bus and L2 bus ratios. The values do not include OV

; AV

and L2AV

suppling power. OV

power is system dependent, but is typically

<10% of V

power. Worst case power consumption, for AV

=15mW and L2AV

=15mW.

Maximum power is measured at V

=2.1V while running an entirely cache-resident, contrived sequence of instructions which keep the execution units maximally busy.

Typical power is an average value measured at V

=AV

=L2AV

=2.0V, OV

=L2OV

=3.3V in a system, executing typical applications and benchmark sequences.

L2 CACHE CONTROL REGISTER (L2CR)

The L2 cache control register, shown in Figure 5, is a supervisor-level, implementation-specifi c SPR used to confi gure
and operate the L2 cache. It is cleared by hard reset or power-on reset.

The L2CR bits are described in Table 1.

FIGURE 5 L2 CACHE CONTROL REGISTER (L2CR)

L2E L2SIZ L2CLK

L2RAM L2I

L20H

L2CTR

0 1 2 3 4

6 7

8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

30 31

L2PE L2DO

L2CTL

L2TS

L2SL

L2BYP

L2IO

L2DRO

L2IP

L2WT L2DF L2CS

Reserved

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White Electronic Designs

WED3C7558M-XBX

August 2002
Rev. 7

TABLE 1: L2CR BIT SETTINGS

Bit

Name

Function

L2E

L2 enable. Enables L2 cache operation (including snooping) starting with the next transaction the L2 cache unit receives. Before
enabling the L2 cache, the L2 clock must be confi gured through L2CR[2CLK], and the L2 DLL must stabilize. All other L2CR bits
must be set appropriately. The L2 cache may need to be invalidated globally.

L2PE

L2 data parity checking enable. Enables parity generation and checking for the L2 data RAM interface. When disabled, generated
parity is always zeros. L2 Parity is supported by WEDC's WED3C7558M-XBX, but is dependent on application.

L2SIZ

L2 size -- Should be set according to the size of the L2 data RAMs used.
11 1 Mbyte - Setting for WED3C7558M-XBX

L2CLK

L2 clock ratio (core-to-L2 frequency divider). Specifi es the clock divider ratio based from the core clock frequency that the L2 data
RAM interface is to operate at. When these bits are cleared, the L2 clock is stopped and the on-chip DLL for the L2 interface is
disabled. For nonzero values, the processor generates the L2 clock and the on-chip DLL is enabled. After the L2 clock ratio is chosen,
the DLL must stabilize before the L2 interface can be enabled. The resulting L2 clock frequency cannot be slower than the clock
frequency of the 60x bus interface.
000 L2 clock and DLL disabled
001

÷ 1

010

÷ 1.5

011 Reserved
100

÷ 2

101

÷ 2.5

110

÷ 3

111 Reserved

L2RAM

L2 RAM type -- Confi gures the L2 RAM interface for the type of synchronous SRAMs used:
· Pipelined (register-register) synchronous burst SRAMs that clock addresses in and clock data out
The 755 does not burst data into the L2 cache, it generates an address for each access.
10 Pipelined (register-register) synchronous burst SRAM Setting for WED3C7558M-XBX

L2DO

L2 data only. Setting this bit enables data-only operation in the L2 cache. For this operation, instruction transactions from the L1
Instruction cache already cached in the L2 cache can hit in the L2, but new instruction transactions from the L1 instruction cache are
treated as cache-inhibited (bypass L2 cache, no L2 checking done). When both L2DO adn L2IO are set, the L2 cache is effectively
locked (cache misses do not cause new entries to be allocated but write hits use the L2).

L2I

L2 global invalidate. Setting L2I invalidates the L2 cache globally by clearing the L2 status bits. This bit must not be set while the L2
cache is enabled. See Motorola's User manual for L2 Invalidation procedure.

L2CTL

L2 RAM control (ZZ enable). Setting L2CTL enables the automatic operation of the L2ZZ (low-power mode) signal for cache RAMs.
Sleep mode is supported by the WED3C7558M-XBX. While L2CTL is asserted, L2ZZ asserts automatically when the device enters
nap or sleep mode and negates automatically when the device exits nap or sleep mode. This bit should not be set when the device is
in nap mode and snooping is to be performed through deassertion of QACK#.

L2WT

L2 write-through. Setting L2WT selects write-through mode (rather than the default write-back mode) so all writes to the L2 cache also
write through to the system bus. For these writes, the L2 cache entry is always marked as exclusive rather than modifi ed. This bit
must never be asserted after the L2 cache has been enabled as previously-modifi ed lines can get remarked as exclusive during
normal operation.

L2TS

L2 test support. Setting L2TS causes cache block pushes from the L1 data cache that result from dcbf and dcbst instructions to be
written only into the L2 cache and marked valid, rather than being written only to the system bus and marked invalid in the L2 cache
in case of hit. This bit allows a dcbz/dcbf instruction sequence to be used with the L1 cache enabled to easily initialize the L2 cache
with any address and data information. This bit also keeps dcbz instructions from being broadcast on the system and single-beat
cacheable store misses in the L2 from being written to the system bus.
0: Setting for the L2 Test support as this bit is reserved for tests.

1415

L2OH

L2 output hold. These bits confi gure output hold time for address, data, and control signals driven to the L2 data RAMs.
00: Least Hold Time Setting for WED3C7558M-XBX

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White Electronic Designs

WED3C7558M-XBX

August 2002
Rev. 7

TABLE 1: L2CR BIT SETTINGS

Bit

Name

Function

L2SL

L2 DLL slow. Setting L2SL increases the delay of each tap of the DLL delay line. It is intended to increase the delay through the DLL
to accommodate slower L2 RAM bus frequencies.
0: Setting for WED3C7558M-XBX because L2 RAM interface is operated above 100 MHz.

L2DF

L2 differential clock. This mode supports the differential clock requirements of late-write SRAMs.
0: Setting for WED3C7558M-XBX because late-write SRAMs are not used.

L2BYP

L2 DLL bypass is reserved.
0: Setting for WED3C7558M-XBX

19-20

Reserved. These bits are implemented but not used; keep at 0 for future compatibility.

L2IO

L2 Instruction-only. Setting this bit enables instruction-only operation in the L2 cache. For this operation, data transactions from the L1
data cache already cached in the L2 cache can hit in the L2 (including writes), but new data transactions (transactions that miss in the
L2) from the L1 data cashe are treated as cache-inhibited (bypass L2 cache, no L2 checking done). When both L2DO and L2IO are
set, the L2 cache is effectively locked (cache misses do not cause new entries to be allocated but write hits use the L2). Note that this
bit can be programmed dynamically.

L2CS

L2 Clock Stop. Setting this bit causes the L2 clocks to the SRAMs to automatically stop whenever the MPC755 enters nap or sleep
modes, and automatically restart when exiting those modes (including for snooping during nap mode). It operates by asynchronously
gating off the L2CLK_OUT [A:B] signals while in nap or sleep mode. The L2SYNC_OUT/SYNC_IN path remains in operation, keeping
the DLL synchronized. This bit is provided as a power-saving alternative to the L2CTL bit and its corresponding ZZ pin, which may not
be useful for dynamic stopping/restarting of the L2 interface from nap and sleep modes due to the relatively long recovery time from
ZZ negation that the SRAM requires.

L2DRO

L2 DLL rollover. Setting this bit enables a potential rollover (or actual rollover) condition of the DLL to cause a checkstop for the
processor. A potential rollover condition occurs when the DLL is selecting the last tap of the delay line, and thus may risk rolling over
to the fi rst tap with one adjustment while in the process of keeping synchronized. Such a condition is improper operation for the DLL,
and, while this condition is not expected, it allows detection for added security. This bit can be set when the DLL is fi rst enabled (set
with the L2CLK bits) to detect rollover during initial synchronization. It could also be set when the L2 cache is enabled (with L2E bit)
after the DLL has achieved its initial lock.

2430

L2CTR

L2 DLL counter (read-only). These bits indicate the current value of the DLL counter (0 to 127). They are asynchronously read when
the L2CR is read, and as such should be read at least twice with the same value in case the value is asynchronously caught in
transition. These bits are intended to provide observability of where in the 128-bit delay chain the DLL is at any given time. Generally,
the DLL operation should be considered at risk if it is found to be within a couple of taps of its beginning or end point (tap 0 or tap
128).

L2IP

L2 global invalidate in progress (read only)--See the Motorola user's manual for L2 Invalidation procedure.

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White Electronic Designs

WED3C7558M-XBX

August 2002
Rev. 7

The AV

and L2AV

power signals are provided on

the WED3C7558M-XBX to provide power to the clock
generation phase-locked loop and L2 cache delay-locked
loop respectively. To ensure stability of the internal clock,
the power supplied to the AV

input signal should be

fi ltered of any noise in the 500kHz to 10 MHz resonant
frequency range of the PLL. A circuit similar to the
one shown in Figure 6 using surface mount capacitors
with minimum Effective Series Inductance (ESL) is
recommended. Multiple small capacitors of equal value

PLL POWER SUPPLY FILTERING

are recommended over a single large value capacitor.
The circuit should be placed as close as possible to the
AV

pin to minimize noise coupled from nearby circuits.

An identical but separate circuit should be placed as close
as possible to the L2AV

pin. It is often possible to route

directly from the capacitors to the AV

pin, which is on the

periphery of the 255 BGA footprint, without the inductance
of vias. The L2AV

pin may be more diffi cult to route but

is proportionately less critical.

FIGURE 6 POWER SUPPLY FILTER CIRCUIT

AVcc (or L2AVcc)

2.2

µF

2.2

µF

GND

Low ESL surface mount capacitors

Vcc

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