INTEGRATED CIRCUITS

TPM754Microcontroller with TrackPoint
microcode from IBM
Preliminary specification
Supersedes data of 1997 Feb 26
IC20 Data Handbook   

1997 Dec 03

Philips Semiconductors

Preliminary specification

Microcontroller with TrackPoint microcode from IBM

The Philips Semiconductors TPM754 is a small package, low cost,
ROM-coded 80C51 with IBM’s TrackPoint pointing algorithms
and control code. TrackPoint is the result of years of human factors
research and innovation at IBM. The result is a “velocity sensitive”
pointing solution more efficient and easier to use than “position
sensitive” devices such as the mouse, the trackball, or the touchpad.

TPM754PIN CONFIGURATION

IBM has licensed Philips Semiconductors to sell microcontrollers
with TrackPoint code. By purchasing a TPM from Philips, thepurchaser becomes a sub-licensee of Philips. The selling price ofPhilips’ TPM includes the royalties for IBM’s intellectual property,
which Philips in turn pays to IBM. Customers for TPMs do not needto sign any licensing agreement with either IBM or Philips. This codeis the intellectual property of IBM, which is covered by numerous
patents, and must be treated accordingly.
The TPM754 contains IBM TrackPoint code, a single module
PCA, a 256 × 8 RAM, 21 I/O lines, two 16-bit counter/timers, a
two-priority level interrupt structure, a full duplex serial channel, an
on-chip oscillator, and an 8-bit D/A converter.

RxD/T0/P3.4

1

28 P3.3

TxD/T1/P3.5

2

27 P3.2

ECI/P3.6

3

26 P3.1

INT1/P3.7

4

25 P3.0

RST

5

24 INT0/P1.0

X2

6

X1

7

VSS

8

ZIN

9

20 XYDACYIN

10

19 ZDAC/ASEL

XIN

11

18 XYSOURCEXYZRAMP 12
AVSS

For identical device without TrackPoint code, see the 8XC754
datasheet.

13

AVCC 1423 CEX/P1.1
PLASTICSHRINKSMALLOUTLINE
PACKAGE

22 VCC
21 P1.2

17 XYDACBIAS
16 VREG15 DECOUPLE

SU00726B

FEATURES• 80C51-based architecture• Small package sizes – 28-pin SSOP
• Power control modes:– Idle mode
– Power-down mode

• 256 × 8 RAM• Two 16-bit auto reloadable counter/timers• Single module PCA counter/timer• Full duplex serial channel• Boolean processor• CMOS and TTL compatible
ORDERING INFROMATIONORDERING CODETEMPERATURE RANGE °C
AND PACKAGEFREQUENCYDRAWINGNUMBERPTPM754 DB

0 to +70, 28-pin Shrink Small Outline Package

3.5 to 12MHz

SOT341-1

For compatible pointing device, contact:
COMPANY
Bokam Engineering
CTS Corporation

IBM is a registered trademark, and TrackPoint is a trademark of IBM Corporation.

1997 Dec 03

1550

+5
14

22

AVCC
15
R1

R16

R15

16
17

2
C6
0.01uF

R12

R13

R19

R4

C7
0.01uF

2
+Y

1551

+X

–X

3
–Y

4
5
6

J6
AMP 487951–6
1
2
3
4
5
6

5

4
1

U2
11

LMC6034

6
1

3

18
21
9
10
11

U2

12

7
R7

20
19
R6

9
C8
0.01uF

10

U2

8

R11

1

RIGHT
2

1

MIDDLE
2

1

LEFT
2

26
27
25

+

+5

U1

DEC

VREG
XYDB

RST

P3.6
P3.3
P1.1

XYS
WIN
ZIN
YIN
XIN
RMP
XYD
ZDAC
P3.1
P3.2
P3.0
AVSS
13

INT0
TXD/T1
INT1
RXD/T0
X2
X1

C5
10uF

R8
100K
5%

VCC

TPM754

+5
+

C4
2.2uF

5
3
28

INVERT Y
INVERT Z

23

TACTILEJ8
BERG 2X2
1
2
3
4
+5

+5
R2
4.7K
5%

24
2
+5
GND

4
1
6
X1
7 12.0MHz

+5

+5
R10
10K
5%

VSS
8

13
12

U2

14

R5

R17

TO MOUSE
R14 J2
10K 6 PIN MINI DIN
5%
5 3
CLK
DATA
1
2
4

6
+5

R18

R9

R20

TO PS\2
R3
4.7K
5%

C2
0.01uFJ1
5 PIN BERG
1 CLK
2 DATA
3 +5
4 COM
5 SHIELD

Philips Semiconductors+5
C3
0.01uF

Microcontroller with TrackPoint microcode from IBM

C1
10uF

SCHEMATIC OF TRACKPOINT SYSTEM

1997 Dec 03+5+

NOTES:
1. Resistor values are dependent on the pointing stick used. The pointing stick manufacturer or Philips Semiconductors can provide these values.
2. R1 may be integrated into some pointing sticks.

Preliminary specification

TPM754SU00815D

Philips Semiconductors

Preliminary specification

Microcontroller with TrackPoint microcode from IBM

TPM754

PIN DESCRIPTIONMNEMONICDIPPIN NO.

TYPE

VSS

8

I

Circuit Ground Potential.

VCC

22

I

Supply voltage during normal, idle, and power-down operation.

21, 23, 24

I/O

24
23

I
O

Port 1: Port 1 is a 3-bit bidirectional I/O port with internal pull-ups on P1.0 and P1.1. Port 1 pins thathave 1s written to them can be used as inputs. As inputs, port 1 pins that are externally pulled low willsource current because of the internal pull-ups (P1.0, P1.1). (See DC Electrical Characteristics: IIL).
Port 1 also serves the special function features listed below (Note: P1.0 does not have the strong
pullup that is on for 2 oscillator periods.):
INT0 (P1.0): External interrupt 0.
CEX (P1.1): PCA clock output.

1–4,
25–28

I/O

3
1

I
I

4
2

I
I

RST

5

I

Reset: A high on this pin for two machine cycles while the oscillator is running resets the device.
(NOTE: The TPM754 does not have an internal reset resistor.)

X1

7

I

Crystal 1: Input to the inverting oscillator amplifier and input to the internal clock generator circuits.

X2

6

O

Crystal 2: Output from the inverting oscillator amplifier.

AVCC

1

14

I

Analog supply voltage and reference input.

AVSS

1

13

I

Analog supply and reference ground.

ZIN

9

I

ZIN: Input to analog multiplexer.

YIN

10

I

YIN: Input to analog multiplexer.

XIN

11

I

XIN: Input to analog multiplexer.

XYZRAMP12OXYZRAMP: Provides a low impedance pulldown to VSS under S/W control.

DECOUPLE

15O

DECOUPLE: Output from regulated supply for connection of decoupling capacitors.

VREG

16

O

VREG: Provides regulated analog supply output.

XYDACBIAS

17OXYDACBIAS: Provides source voltage for bias of external circuitry.

XYSOURCE18O

XYSOURCE: Provides source voltage from regulated analog supply.

ZDAC

19

O

ZDAC: Switchable output from the internal DAC.

XYDAC

20

O

XYDAC: Non-switchable output from the internal DAC.

P1.0–P1.2

P3.0–P3.7

NAME AND FUNCTIONPort 3: Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. Port 3 pins that have 1s written tothem are pulled high by the internal pull-ups and can be used as inputs. As inputs, port 3 pins that are
externally being pulled low will source current because of the pull-ups. (See DC Electrical
Characteristics: IIL). (Note: P3.5 does not have the strong pullup that is on for 2 oscillator periods.)
Port 3 also serves the special function as listed below:
ECI (P3.6): External PCA clock input.
RxD/T0 (P3.4): Serial port receiver data input.
Timer 0 external clock input.
INT1: External interrupt 1.
TxD/T1 (P3.5): Serial port transmitter data.
Timer 1 external clock input.

NOTE:
1. AVSS (reference ground) must be connected to 0V (ground). AVCC (reference input) cannot differ from VCC by more than ±0.2V, and must bein the range 4.5V to 5.5V.

1997 Dec 03

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Philips Semiconductors

Preliminary specification

Microcontroller with TrackPoint microcode from IBM

The DAC is an 8-bit device and its output appears on the XYDAC
pin. In addition, the DAC output may also be routed to the ZDAC pin
by means of bit AC6 in the ACON0 register. The DAC output is notbuffered, so external load impedances should be taken into
consideration when using either of these outputs.

OSCILLATOR CHARACTERISTICS
X1 and X2 are the input and output, respectively, of an inverting
amplifier which can be configured for use as an on-chip oscillator.
To drive the device from an external clock source, X1 should be
driven while X2 is left unconnected. There are no requirements on
the duty cycle of the external clock signal, because the input to theinternal clock circuitry is through a divide-by-two flip-flop. However,minimum and maximum high and low times specified in the data
sheet must be observed.

A 3-input multiplexer is provided, whose output is connected to thepositive reference of a comparator. The multiplexer output is
controlled by bits MUX2:0 of ACON1. A bandgap reference supplies
the negative reference of the comparator. The output of thecomparator may be used the trigger the capture input of module 4 of
the PCA.

IDLE MODE

A low impedance pulldown is supplied at the XYZRAMP pin and iscontrolled by bit AC5 of ACON0.

The TPM754 includes the 80C51 power-down and idle mode
features. In idle mode, the CPU puts itself to sleep while all of the
on-chip peripherals except the D/A stays active. The functions that
continue to run while in the idle mode are the timers and theinterrupts. The instruction to invoke the idle mode is the last
instruction executed in the normal operating mode before the idle
mode is activated. The CPU contents, the on-chip RAM, and all of
the special function registers remain intact during this mode. The
idle mode can be terminated either by any enabled interrupt (atwhich time the process is picked up at the interrupt service routine
and continued), or by a hardware reset which starts the processor in
the same manner as a power-on reset. Upon powering-up thecircuit, or exiting from idle mode, sufficient time must be allowed forstabilization of the internal analog reference voltages before a D/Aconversion is started.

The functions of the analog section are controlled by the IBM
TrackPoint code embedded within the Philips TPM754.

PC BOARD LAYOUT CONSIDERATIONSThe TrackPoint is a low-level analog circuit. While not difficult toimplement, careful consideration should be given to circuit board
layout to obtain proper operation of the TrackPoint. The
considerations are similar to that used for radio frequency
application. The circuit should be located far from the CPU andvideo lines, and should also be shielded from any digital signals. A
100µV pulse picked up every 3 or 4 seconds is sufficient to cause
cursor drift. A good circuit board layout will result in a circuit that isvery stable and will hold the cursor on a pixel for days at a time.
However, the autorouters of most software board layout packages
will not do an adequate job, and manual routing of this portion of themotherboard is recommended.

I/O Ports
The I/O pins provided by the TPM754 consist of port 1 and port 3.
Port 1
Port 1 is a 3-bit bidirectional I/O port and includes alternate functions
on some pins of this port. Pins P1.0 and P1.1 are provided withinternal pullups while the remaining pin (P1.2) has an open drain
output structure. The alternate functions for port 1 are:

The TPM754 has excellent supply regulation for the analog portionsof the TrackPoint circuit. However, care should be taken with respect
to the circuit ground to avoid voltage shifts due to non-TrackPoint
loads. The analog part of the circuit must have its own groundplane, isolated from everything else and connected to the main
ground at just one point (no ground loops). All of the analog portionof the TrackPoint circuit, and nothing else, must be over thisground island.

INT0 – External interrupt 0.
CEX – PCA clock output.
Port 3
Port 3 is an 8-bit bidirectional I/O port structure.

No digital traces can pass though the analog area on any level fromthe ground plane out. The circuit should be confined to one side of
the ground plane, preferably on the first interior layer, with theground plane next. The circuit should be powered only at a single
point (pin 14), and that power should be filtered to ground before itcomes onto the analog area.

The alternate functions for port 3 are:RxD – Serial port receiver data input.
T1 – Timer 1 external clock input.
INT1 – External interrupt 1.
TxD – Serial port transmitter data.
T0 – Timer 0 external clock input.
ECI – PCA external clock input.

The signal lines from the TrackPoint sensor stick can be sensitive to
pickup, and should be run close together, and not too close to digital
lines. A grounded guard trace is a good idea. Most important, thestick common line is not a ground line, but rather a signal line,
although it will eventually connect to the analog ground. A commonand serious error is to treat it as ground, connecting it to a generalground at some convenient point.

Analog Section
The analog section of the TPM754, shown in Figure 1, consists offour major elements: a bandgap referenced voltage regulator, an
8-bit DAC, an input multiplexer and comparator, and a low
impedance pulldown device.

The layout should be designed to keep things compact and minimize
trace lengths. The whole circuit, analog and digital, will fit
comfortably within 2cm × 3cm. In some situations, it may bedesirable to put the circuit on a separate card instead of on themotherboard. In this case, a shielded cable should provide the bestmeans of connecting the stick signals to the circuit card.

The bandgap voltage regulator uses the AVCC pin as its supply andproduces a regulated output on the VREG pin. The regulator also
supplies the analog supply voltage for the DAC. The regulator may
be switched on/off by means of the AC1 bit in the analog control
register (ACON0). The regulator output may also be supplied to the
XYDACBIAS and XYSOURCE pins by means of bits AC3 and AC4,
respectively. The DECOUPLE pin is provided for decoupling theregulator output.

1997 Dec 03

TPM7541553

Philips Semiconductors

Preliminary specification

Microcontroller with TrackPoint microcode from IBM

TPM754AVCC
BANDGAP REF*AC1
DECOUPLE
AC2
VREG

20K

AC3

10K

XYDACBIASAC4XYSOURCE
1K

DCON 7:0 (84H)

XYDAC

AC6

ZDAC

ZIN

YIN

AC7

ANALOGMUX

TO PCA TRIGGER

XIN

BANDGAP REF
EXT
MUX0
MUX1
MUX2

XYZRAMP
AC5*ENABLED/DISABLED BY AC0

SU00765A

Figure 1. Analog Section

ALTERNATE
OUTPUTFUNCTION

READ
LATCH

VDD
INTERNAL*
PULL-UP

INT. BUS

D

Q
PIN

LATCH
WRITE TO
LATCH

READ
PIN

CL

Q

ALTERNATE INPUTFUNCTION*PINS LISTED AS OPEN DRAIN WILL NOT HAVE THIS PULLUP

SU00671

Figure 2. Typical Port Bit Latches and I/O Buffers

1997 Dec 031554

Philips Semiconductors

Preliminary specification

Microcontroller with TrackPoint microcode from IBM

TPM754

ABSOLUTE MAXIMUM RATINGS1, 3, 4
PARAMETERRATING

UNIT

Storage temperature range–65 to +150

°C

Voltage from VCC to VSS–0.5 to +6.5

V

Voltage from any pin to VSSPower dissipation–0.5 to VCC + 0.5

V

1.0

W

DC ELECTRICAL CHARACTERISTICS
Tamb = 0°C to +70°C, AVCC = 5V ±5, AVSS = 0V4
VCC = 5V ± 10%, VSS = 0V
SYMBOL
ICC

PARAMETERTEST CONDITIONSLIMITS4
MIN

TYP1

MAX

UNIT

Supply current (see Figure 5)

Inputs
VIL

Input low voltage, port 1, 3

–0.5

0.2VCC–0.1

V

VIH

Input high voltage, port 1, 3

0.2VCC+0.9

VCC+0.5

V

VIH1

Input high voltage, X1, RST

0.7VCC

VCC+0.5

V

Outputs
VOL

Output low voltage, port 3, 1.2

IOL = 1.6mA2

0.45

V

VOL1

Output low voltage, port 1.0, 1.1

IOL = 3.2mA2

0.45

V

VOH

Output high voltage, ports 3, 1.0, 1.1

IOH = –60µA,

ILI

Input leakage current, port 1, 3, RST

0.45 < VIN < VCC

±10

µA

CIO

Pin capacitance

Test freq = 1MHz,
Tamb = 25°C

10

pF

2.4

V

NOTES:
1. Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only andfunctional operation of the device at these or any conditions other than those described in the AC and DC Electrical Characteristics sectionof this specification is not implied.
2. Under steady state (non-transient) conditions, IOL must be externally limited as follows:
10mA
Maximum IOL per port pin:
Maximum IOL per 8-bit port:
26mA
67mA
Maximum total IOL for all outputs:
If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater than the listed
test conditions.
3. This product includes circuitry specifically designed for the protection of its internal devices from the damaging effects of excessive static
charge. Nonetheless, it is suggested that conventional precautions be taken to avoid applying greater than the rated maxima.
4. Parameters are valid over operating temperature range unless otherwise specified. All voltages are with respect to VSS unless otherwise
noted.
5. Power-down ICC is measured with all output pins disconnected; X2, X1 n.c.; RST = VSS.
6. ICC is measured with all output pins disconnected; X1 driven with tCLCH, tCHCL = 5ns, VIL = VSS + 0.5V, VIH = VCC – 0.5V; X2 n.c.;
RST = VCC. ICC will be slightly higher if a crystal oscillator is used.
7. Idle ICC is measured with all output pins disconnected; X1 driven with tCLCH, tCHCL = 5ns, VIL = VSS + 0.5V, VIH = VCC – 0.5V; X2 n.c.;
RST = VSS.
8. Pin 9, 10, 11, and 21; VIN ≤ VREG.

1997 Dec 03

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Philips Semiconductors

Preliminary specification

Microcontroller with TrackPoint microcode from IBM

TPM754ANALOG SECTION ELECTRICAL CHARACTERISTICS
Tamb = 0°C to +70°C; VCC = 5V ± 10%, VSS = 0V

LIMITS4SYMBOLPARAMETERTEST CONDITIONS

MIN

TYP1

MAX

4.5

–

5.5

UNIT

Analog Inputs
AVCC

Analog supply voltage

V

330

–

3K

Ω

AC0 = 0 IC only

–

1.2

2.5

mA

AC0 = 1

–

–

10

µA

IVREG = 13mA

3.6

3.8

4.3

V

CDEC = 10µF

–

60

100

mA

Stability requirement

–

10

–

µF

RDSONQ1–

7

ILEAKAGEQ1–10

Sensor resistor
IAVCC

Regulator
VREG
ICHARGE

Decouple current

CDECOUPLE

12

Ω

+10

µA

+10

µA

–

–40

–

dB

1.14

1.26

1.38

V

MUX impedance–1

VIN ≤ VREG

–10

ILEAKAGEQ2

–10

PSRR

100Hz

MUX and Comparator
Comparator trip point

ILEAKAGEMUX

4

kΩ

+10

µA

–

–

bits

Digital-to-Analog Conversion
ZDAC, XYDAC monotonicity

8

ZDAC switch impedance

–

75

200

Ω

DAC output resistance

–

2.7

5

kΩ

ZDAC switch leakage

–10

+10

µA

XYZRAMP impedance

–

100

Ω

XYZRAMP leakage

–10

+10

µA

XYDACBIAS impedance

–

25

Ω

XYDACBIAS leakage

–10

+10

µA

XYSOURCE impedance

–

400

Ω

XYSOURCE leakage

–10

+70

µA

Switches
33

13

200

AC ELECTRICAL CHARACTERISTICS
Tamb = 0°C to +70°C, VCC = 5V ±10%, VSS = 0V4
VARIABLE CLOCKSYMBOL
1/tCLCL

PARAMETER
Oscillator frequency:

MIN

MAX

UNIT

3.5

12

MHz

External Clock (Figure 3)tCHCXHigh time

20

ns

tCLCX

Low time

20

ns

tCLCH

Rise time

20

ns

tCHCL

Fall time

20

ns

1997 Dec 03

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Philips Semiconductors

Preliminary specification

Microcontroller with TrackPoint microcode from IBM

TPM754

EXPLANATION OF THE AC SYMBOLS
Each timing symbol has five characters. The first character is always‘t’ (= time). The other characters, depending on their positions,indicate the name of a signal or the logical status of that signal.
The designations are:C – Clock
D – Input data
H – Logic level highL – Logic level low
Q – Output data
T – TimeV – Valid
X – No longer a valid logic level
Z – FloattCLCX

VCC –0.5
0.2 VCC + 0.9
0.2 VCC – 0.1

tCHCX

0.45V

tCLCH

tCHCL
tCLCL

SU00297

Figure 3. External Clock Drive

VCC –0.5

0.2 VCC + 0.9
0.2 VCC – 0.1

0.45V

SU00307

Figure 4. AC Testing Input/Output

MAX ACTIVE ICC6

20
18
16
14
12
ICC mA
10

TYP ACTIVE ICC686MAX IDLE ICC742

TYP IDLE ICC7
4MHz

8MHz

12MHz

FREQ

Figure 5. ICC vs. FREQ
Maximum ICC values taken at VCC = 5.5V and worst case temperature.
Typical ICC values taken at VCC = 5.0V and 25°C.
Notes 6 and 7 refer to AC Electrical Characteristics.
1997 Dec 03

1557

SU00739

Philips Semiconductors

Preliminary specification

Microcontroller with TrackPoint microcode from IBM

SSOP28: plastic shrink small outline package; 28 leads; body width 5.3mm

1997 Dec 03

1558

TPM754

SOT341-1

Philips Semiconductors

Preliminary specification

Microcontroller with TrackPoint microcode from IBM

NOTES

1997 Dec 03

1559

TPM754

Philips Semiconductors

Preliminary specification

Microcontroller with TrackPoint microcode from IBM

TPM754

DEFINITIONS
Data Sheet Identification

Product Status

Definition

Objective Specification

Formative or in Design

This data sheet contains the design target or goal specifications for product development. Specifications
may change in any manner without notice.

Preliminary Specification

Preproduction ProductThis data sheet contains preliminary data, and supplementary data will be published at a later date. Philips
Semiconductors reserves the right to make changes at any time without notice in order to improve designand supply the best possible product.

Product Specification

Full Production

This data sheet contains Final Specifications. Philips Semiconductors reserves the right to make changes
at any time without notice, in order to improve design and supply the best possible product.

Philips Semiconductors and Philips Electronics North America Corporation reserve the right to make changes, without notice, in the products,
including circuits, standard cells, and/or software, described or contained herein in order to improve design and/or performance. Philips
Semiconductors assumes no responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright,
or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask
work right infringement, unless otherwise specified. Applications that are described herein for any of these products are for illustrative purposes
only. Philips Semiconductors makes no representation or warranty that such applications will be suitable for the specified use without further testingor modification.
LIFE SUPPORT APPLICATIONS
Philips Semiconductors and Philips Electronics North America Corporation Products are not designed for use in life support appliances, devices,or systems where malfunction of a Philips Semiconductors and Philips Electronics North America Corporation Product can reasonably be expected
to result in a personal injury. Philips Semiconductors and Philips Electronics North America Corporation customers using or selling Philips
Semiconductors and Philips Electronics North America Corporation Products for use in such applications do so at their own risk and agree to fully
indemnify Philips Semiconductors and Philips Electronics North America Corporation for any damages resulting from such improper use or sale.
 Copyright Philips Electronics North America Corporation 1997
All rights reserved. Printed in U.S.A.

Philips Semiconductors
811 East Arques Avenue
P.O. Box 3409
Sunnyvale, California 94088–3409
Telephone 800-234-7381

  
1997 Dec 03 
1560