ADUC836BS Analog Devices Inc, ADUC836BS Datasheet - Page 37

• Manufacturer Part Number: ADUC836BS
• Description: IC ADC DUAL 16BIT W/MCU 52-MQFP
• Manufacturer: Analog Devices Inc
• Series: MicroConverter® ADuC8xxr

Specifications of ADUC836BS

• Rohs Status: RoHS non-compliant
• Core Processor: 8052
• Core Size: 8-Bit
• Speed: 12.58MHz
• Connectivity: EBI/EMI, I²C, SPI, UART/USART
• Peripherals: POR, PSM, PWM, Temp Sensor, WDT
• Number Of I /o: 34
• Program Memory Size: 62KB (62K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 2.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.25 V
• Data Converters: A/D 7x16b; D/A 1x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 52-MQFP, 52-PQFP

PWM MODES OF OPERATION
Mode 0: PWM Disabled
The PWM is disabled, allowing P1.0 and P1.1 to be used as normal.
Mode 1: Single Variable Resolution PWM
In Mode 1, both the pulse length and the cycle time (period) are
programmable in user code, allowing the resolution of the PWM
to be variable.
PWM1H/L sets the period of the output waveform. Reducing
PWM1H/L reduces the resolution of the PWM output but
increases the maximum output rate of the PWM (e.g., setting
PWM1H/L to 65536 gives a 16-bit PWM with a maximum
output rate of 192 Hz (12.583 MHz/65536). Setting PWM1H/L
to 4096 gives a 12-bit PWM with a maximum output rate of
3072 Hz (12.583 MHz/4096)).
PWM0H/L sets the duty cycle of the PWM output waveform, as
shown in Figure 27.
Mode 2: Twin 8-Bit PWM
In Mode 2, the duty cycle of the PWM outputs and the resolution
of the PWM outputs are both programmable. The maximum
resolution of the PWM output is eight bits.
PWM1L sets the period for both PWM outputs.Typically this will
be set to 255 (FFH) to give an 8-bit PWM, although it is possible
to reduce this as necessary. A value of 100 could be loaded here
to give a percentage PWM (i.e., the PWM is accurate to 1%).
The outputs of the PWM at P1.0 and P1.1 are shown in Figure 28.
As can be seen, the output of PWM0 (P1.0) goes low when the
PWM counter equals PWM0L. The output of PWM1 (P1.1)
goes high when the PWM counter equals PWM1H and goes low
again when the PWM counter equals PWM0H. Setting PWM1H
to 0 ensures that both PWM outputs start simultaneously.
REV. A
Figure 27. PWM in Mode 1
PWM COUNTER
PWM1H/L
PWM0H/L
P1.0
0
–37–
Mode 3: Twin 16-Bit PWM
In Mode 3, the PWM counter is fixed to count from 0 to 65536,
giving a fixed 16-bit PWM. Operating from the 12.58 MHz core
clock results in a PWM output rate of 192 Hz.The duty cycle of the
PWM outputs at P1.0 and P1.1 is independently programmable.
As in Figure 29, while the PWM counter is less than PWM0H/L,
the output of PWM0 (P1.0) is high. Once the PWM counter
equals PWM0H/L, PWM0 (P1.0) goes low and remains low until
the PWM counter rolls over.
Similarly, while the PWM counter is less than PWM1H/L, the
output of PWM1 (P1.1) is high. Once the PWM counter equals
PWM1H/L, PWM1 (P1.1) goes low and remains low until the
PWM counter rolls over.
In this mode, both PWM outputs are synchronized (i.e., once the
PWM counter rolls over to 0, both PWM0 (P1.0) and PWM1
(P1.1) will go high).
Figure 28. PWM Mode 2
Figure 29. PWM Mode 3
PWM COUNTER
PWM COUNTER
ADuC836
65536
PWM1H/L
PWM0H/L
0
P1.0
P1.1
PWM1L
PWM0H
PWM0L
PWM1H
P1.0
P1.1
0