Specifications

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ESS Technology, Inc. SAM0023-122898 25

ES1869 DATA SHEET

PERIPHERAL INTERFACING

MONO_IN and MONO_OUT

MONO_IN is a line-level analog input. MONO_IN is an

input to the playback mixer and the record mixer. The

mixer volumes are controlled by mixer registers 6Dh

(playback) and 6Fh (record).

Alternately, MONO_IN can be mixed with AOUT_L and

AOUT_R after the master volume stage. Bit 0 of mixer

directly (unity gain) with AOUT_L and AOUT_R.

A third use of MONO_IN is as an input to the left channel

ADC in full-duplex DSP serial port mode. In this

application, MONO_IN is typically a line-level microphone

input (external preamp). MONO_IN can be selected as an

input in serial port mode by setting bits 6 and 7 of mixer

the recording source select and record volume stages.

MONO_IN directly drives the left channel switched-

capacitor filter. The output of the switched-capacitor filter

is FOUT_L, which is AC-coupled externally to CIN_L, the

left channel ADC input.

MONO_OUT is a line-level mono output. During power-

down or during opamp calibration, MONO_OUT is held at

CMR (as are AOUT_L and AOUT_R) by an internal, high-

impedance resistor divider. MONO_OUT can be selected

from among four sources by bits 2 and 1 of mixer register

7Dh.

Normally bits 2:1 are both zero, so that MONO_OUT is

muted.

When bit 2 is 0 and bit 1 is 1, MONO_OUT is a buffered

version of input pin CIN_R. CIN_R is typically the right

channel DAC output, filtered by the first channel switched-

capacitor filter. If the right channel is used for ADC, CIN_R

will be the right channel ADC input. MONO_OUT can be

used in this application as digitized audio playback

through the first channel DMA, right channel DAC.

When bit 2 is 1 and bit 1 is 0, MONO_OUT is a buffered

version of the second channel, right channel DAC. In this

case, the second channel DMA can play digitized audio

through MONO_OUT.

When bit 2 is 1 and bit 1 is 1, MONO_OUT is a buffered

version of a mono mix of the record level stage left and

right outputs. This gives the utmost flexibility in the source

or sources of MONO_OUT. The record source select and

record levels can be programmed to generate any

combination of sources and volumes for MONO_OUT.

Spatializer

VBX™ Audio Processor

The ES1869 incorporates an embedded Spatializer

VBX™ stereo audio processor provided by Desper

Products, Inc., a subsidiary of Spatializer Audio Laboratories,

Inc. It is positioned between the output of the playback

mixer and the master volume controls and it produces a

wider perceived stereo effect.

The 3-D effect is enabled by register 50h bit 3. The amount

of effect is controlled by directly programming 3-D Level

Hardware and Master Volume Control

Three external pins, VOLUP, VOLDN, and MUTE can be

connected to external momentary switches to ground to

implement hardware master volume controls. Pressing

one of these buttons produces a low signal to one of the

inputs and thereby changes the master volume.

In one mode the MUTE input can be replaced by the state

where both VOLUP and VOLDN inputs are low.

The up and down buttons produce a single step change in

volume when they are first pressed. If these buttons are

held down, they enter a fast-scrolling mode. The single

step change can be either one volume unit (.75 dB) or

three volume units (2.25 dB). In scrolling mode, the step

change is always one volume unit.

The three inputs have debounce circuitry within the

ES1869. Hold each input low for 40 milliseconds or more

for it to be recognized as a valid button press. Hold each

input high for 40 milliseconds or more between button

presses. A software option allows the debounce time to be

reduced from 40 milliseconds to 10 microseconds.

Normally the hardware volume controls directly change

the master volume registers and produce an interrupt at

each change. However, the ES1869 can be programmed

so that the hardware volume controls do not directly

change the master volume registers. This is called “split

mode”, in which the hardware volume control counters are

split from the master volume registers. Pressing a

hardware volume control button changes the hardware

volume counters and produces an interrupt. The host

software can read the hardware volume counters and

update the master volume registers as needed. Split mode

is enabled by bit 7 of mixer register 64h.

Mixer Register 7Dh

MONO_OUT Source

Bit 2 Bit 1

0 0 Mute (CMR)

0 1 First channel filter output

(actually CIN_R pin)

1 0 Second channel DAC, right channel

1 1 Mono mix of record level stage outputs