P87C591VFA/00,512 NXP Semiconductors, P87C591VFA/00,512 Datasheet - Page 122

• Manufacturer Part Number: P87C591VFA/00,512
• Description: IC 80C51 MCU 16K OTP 44-PLCC
• Manufacturer: NXP Semiconductors
• Series: 87Cr

Specifications of P87C591VFA/00,512

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 12MHz
• Connectivity: CAN, EBI/EMI, I²C, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: OTP
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 4.75 V ~ 5.25 V
• Data Converters: A/D 6x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-PLCC
• Processor Series: P87C5x
• Core: 80C51
• Data Bus Width: 8 bit
• Data Ram Size: 512 B
• Interface Type: CAN, I2C, UART
• Maximum Clock Frequency: 12 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 3
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 6 Channel
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details
• Other names: 568-1256-5; 935268182512; P87C591VFAA

Philips Semiconductors
18 PULSE WIDTH MODULATED OUTPUTS
The P8xC591 contains two Pulse Width Modulated (PWM)
output channels (see Fig.47). These channels generate
pulses of programmable length and interval. The repetition
frequency is defined by an 8-bit prescaler PWMP, which
supplies the clock for the counter. The prescaler and
counter are common to both PWM channels. The 8-bit
counter counts modulo 255, i.e., from 0 to 254 inclusive.
The value of the 8-bit counter is compared to the contents
of two registers: PWM0 and PWM1.
Provided the contents of either of these registers is greater
than the counter value, the corresponding PWM0 or
PWM1 output is set LOW. If the contents of these registers
are equal to, or less than the counter value, the output will
be HIGH. The pulse-width-ratio is therefore defined by the
contents of the registers PWM0 and PWM1. The
pulse-width-ratio is in the range of
be programmed in increments of
Buffered PWM outputs may be used to drive DC motors.
The rotation speed of the motor would be proportional to
the contents of PWMn. The PWM outputs may also be
configured as a dual DAC.
2000 Jul 26
handbook, full pagewidth
Single-chip 8-bit microcontroller with CAN controller
Fig.47 Functional diagram of Pulse Width Modulated outputs.
f CLK
1
0
255
255
.
PRESCALER
to
PWMP
255
255
and may
8-BIT COMPARATOR
8-BIT COMPARATOR
8-BIT COUNTER
122
PWM0
PWM1
In this application, the PWM outputs must be integrated
using conventional operational amplifier circuitry. If the
resulting output voltages have to be accurate, external
buffers with their own analog supply should be used to
buffer the PWM outputs before they are integrated.
The repetition frequency f
given by:
This gives a repetition frequency range of 184 Hz to
47 kHz (at f
with either 00H or FFH, the PWM channels will output a
constant HIGH or LOW level, respectively. Since the 8-bit
counter counts modulo 255, it can never actually reach the
value of the PWM registers when they are loaded with
FFH.
When a compare register (PWM0 or PWM1) is loaded with
a new value, the associated output is updated
immediately. It does not have to wait until the end of the
current counter period. Both PWMn output pins are driven
by push-pull drivers. These pins are not used for any other
purpose.
CLK
f
PWM
= 12 MHz). By loading the PWM registers
OUTPUT
BUFFER
OUTPUT
BUFFER
=
--------------------------------------------------- -
PWMP
PWM
f
CLK
MHI048
, at the PWMn outputs is
+
PWM0
PWM1
1
Preliminary Specification
255
P8xC591