PIC16F1936T-E/SO View Datasheet(PDF) - Microchip Technology

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Description

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PIC16F1936T-E/SO

28/40/44-Pin Flash-Based, 8-Bit CMOS Microcontrollers with LCD Driver and nanoWatt XLP™ Technology

Microchip Technology 

13.0 DIGITAL-TO-ANALOG

CONVERTER (DAC) MODULE

The Digital-to-Analog Converter supplies a variable

voltage reference, ratiometric with VDD, with 32 select-

able output levels. The output of the DAC can be con-

figured to supply a reference voltage to the following:

• Comparator positive input

• ADC input channel

• DACOUT device pin

The Digital-to-Analog Converter (DAC) can be enabled

by setting the DACEN bit of the DACCON0 register.

13.1 Output Voltage Selection

The DAC has 32 voltage level ranges. The 32 levels

are set with the DACR<4:0> bits of the DACCON1

register.

The DAC output voltage is determined by the following

equations:

EQUATION 13-1:

VOUT = ⎝⎛(VSOURCE+ – VSOURCE-) × D-----A----C-2---R-∧---<--5--4---:-0--->--⎠⎞

+ VSOURCE-

VSOURCE+ = VDD, VREF+ or FVR1

VSOURCE+ = VSS or VREF-

13.2 Output Clamped to VSS

The DAC output voltage can be set to Vss with no

power consumption by setting the DACEN bit of the

DACCON0 register to ‘0’: This allows the comparator to

detect a zero-crossing while not consuming additional

current from the DAC.

13.3 Output Ratiometric to VDD

The DAC is VDD derived and therefore, the DAC output

changes with fluctuations in VDD. The tested absolute

accuracy of the DAC can be found in Section 28.0

“Electrical Specifications”.

13.4 Voltage Reference Output

The DAC can be output to the device DACOUT pin by

setting the DACOE bit of the DACCON0 register to ‘1’.

Selecting the reference voltage for output on the

DACOUT pin automatically overrides the digital output

buffer and digital input threshold detector functions of

that pin. Reading the DACOUT pin when it has been

configured for reference voltage output will always

return a ‘0’.

PIC16F193X/LF193X

Due to the limited current drive capability, a buffer must

be used on the voltage reference output for external

connections to DACOUT. Figure 13-1 shows an exam-

ple buffering technique.

13.5 Operation During Sleep

When the device wakes up from Sleep through an

interrupt or a Watchdog Timer time-out, the contents of

the DACCON0 register are not affected. To minimize

current consumption in Sleep mode, the voltage

reference should be disabled.

13.6 Effects of a Reset

A device Reset affects the following:

• Voltage reference is disabled

• Fixed voltage reference is disabled

• DAC is removed from the DACOUT pin

• The DACR<4:0> range select bits are cleared

© 2009 Microchip Technology Inc.

Preliminary

DS41364B-page 151

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