TPM749 NXP Semiconductors, TPM749 Datasheet - Page 5

• Manufacturer Part Number: TPM749
• Description: Microcontroller With Trackpoint Microcode From Ibm
• Manufacturer: NXP Semiconductors

*
Philips Semiconductors
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 the
internal 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.
IDLE MODE
The TPM 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 A/D and PWM stay active. The functions that
continue to run while in the idle mode are Timer 0, Timer I, and the
interrupts. 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 (at
which 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 the
circuit, or exiting from idle mode, sufficient time must be allowed for
stabilization of the internal analog reference voltages before an A/D
conversion is started.
POWER-DOWN MODE
In the power-down mode, the oscillator is stopped and the
instruction to invoke power-down is the last instruction executed.
Only the contents of the on-chip RAM are preserved. A hardware
reset is the only way to terminate the power-down mode. The control
bits for the reduced power modes are in the special function register
PCON.
Table 1. External Pin Status During Idle and
1996 May 01
Idle
Power-down
Microcontroller with TrackPoint
Except for PWM output (P0.4).
WRITE TO
INT. BUS
MODE
LATCH
LATCH
READ
READ
PIN
Power-Down Modes
CL
D
Port 0*
LATCH
ALTERNATE INPUT
P1.X
Data
Data
FUNCTION
Q
Q
ALTERNATE
FUNCTION
OUTPUT
Port 1
Data
Data
Figure 1. Port Bit Latches and I/O Buffers
V
DD
INTERNAL
Port 2
PULL-UP
Data
Data
microcode from IBM
P1.X
PIN
5
I/O Ports
The I/O pins provided by the TPM consist of port 0, port 1, and
port 3.
Port 0
Port 0 is a 5-bit bidirectional I/O port and includes alternate functions
on some pins of this port. Pins P0.3 and P0.4 are provided with
internal pullups while the remaining pins (P0.0, P0.1, and P0.2) have
open drain output structures. The alternate function for port P0.4 is
PWM output.
If the alternate function PWM is not being used, then this pin may be
used as an I/O port.
Port 1
Port 1 is an 8-bit bidirectional I/O port whose structure is identical to
the 80C51, but also includes alternate input functions on all pins.
The alternate pin functions for port 1 are:
P1.0-P1.4 - ADC0-ADC4 - A/D converter analog inputs
P1.5 INT0 - external interrupt 0 input
P1.6 INT1 - external interrupt 1 input
P1.7 - T0 - timer 0 external input
If the alternate functions INT0, INT1, or T0 are not being used, these
pins may be used as standard I/O ports. It is necessary to connect
AV
P1.6, and P1.7 pins as standard I/O pins. When the A/D converter is
enabled, the analog channel connected to the A/D may not be used
as a digital input; however, the remaining analog inputs may be used
as digital inputs. They may not be used as digital outputs. While the
A/D is enabled, the analog inputs are floating.
Port 3
Port 3 is an 8-bit bidirectional I/O port whose structure is identical to
the 80C51. Note that the alternate functions associated with port 3
of the 80C51 have been moved to port 1 of the TPM (as applicable).
See Figure 1 for port bit configurations.
WRITE TO
CC
INT. BUS
LATCH
LATCH
and AV
READ
READ
PIN
SS
to V
CC
CL
D
LATCH
ALTERNATE INPUT
and V
P0.X
FUNCTION
Q
Q
SS
ALTERNATE
FUNCTION
, respectively, in order to use P1.5,
OUTPUT
Product specification
TPM749
SU00306
P0.X
PIN