P89LPC934 PHILIPS [NXP Semiconductors], P89LPC934 Datasheet - Page 55

• Manufacturer Part Number: P89LPC934
• Description: 8-bit microcontroller with accelerated two-clock 80C51 core 4 kB/8 kB 3 V byte-erasable Flash with 8-bit A/D converters
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
9397 750 15113
Product data sheet
9.5.3 Edge triggered
9.5.4 Dual start immediately (P89LPC935/936)
9.6 Boundary limits interrupt
9.7 DAC output to a port pin with high output impedance
9.8 Clock divider
9.9 Power-down and Idle mode
An A/D conversion is started by rising or falling edge of P1.4. Once a conversion has
started, additional edge triggers are ignored until the conversion has completed. The edge
triggered start mode is available in all A/D operating modes.
Programming this mode starts a synchronized conversion of both A/D converters.This
start mode is available in all A/D operating modes. Both A/D converters must be in the
same operating mode. In the continuous conversion modes, both A/D converters must
select an identical number of channels. Any trigger of either A/D will start a simultaneous
conversion of both A/Ds.
Each of the A/D converters has both a high and low boundary limit register. After the four
MSBs have been converted, these four bits are compared with the four MSBs of the
boundary high and low registers. If the four MSBs of the conversion are outside the limit
an interrupt will be generated, if enabled. If the conversion result is within the limits, the
boundary limits will again be compared after all 8 bits have been converted. An interrupt
will be generated, if enabled, if the result is outside the boundary limits. The boundary limit
may be disabled by clearing the boundary limit interrupt enable.
Each A/D converter’s DAC block can be output to a port pin. In this mode, the ADxDAT3
register is used to hold the value fed to the DAC. After a value has been written to the DAC
(written to ADxDAT3), the DAC output will appear on the channel 3 pin.
The A/D converter requires that its internal clock source be in the range of 500 kHz to
3.3 MHz to maintain accuracy. A programmable clock divider that divides the clock
from 1 to 8 is provided for this purpose.
In Idle mode the A/C converter, if enabled, will continue to function and can cause the
device to exit Idle mode when the conversion is completed if the A/D interrupt is enabled.
In Power-down mode or Total Power-down mode, the A/D does not function. If the A/D is
enabled, it will consume power. Power can be reduced by disabling the A/D.
Rev. 06 — 20 June 2005
8-bit microcontroller with accelerated two-clock 80C51 core
P89LPC933/934/935/936
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
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