HT83F22 Datasheet, PDF (137/158 Pages) Holtek Semiconductor Inc – A/D Type Recorder 8-Bit Flash MCU

HT83F22
A/D Type Recorder 8-Bit Flash MCU
MICIN
0.1uF
0.1uF
AIN
MOUT
MIN
0.55 VDD ½ VDD
RGS[2:0] ENBPA
2
Amp
Ref_Gen
FILCLK
PD
From Timer2
ADINS
0
1
4Order LPF
Pre-
Amp
2.2uF
AGC
AGC
FILOUT
To ADC
ENBRES
The MIN pin is the amplifier microphone input pin to which external microcphones can be AC-
coupled using a series capacitor. The Microphone signal is amplified and output on the MOUT pin.
The voltage gain of the Pre-Amp is determined by the voltage level on the AGC pin. An external
capacitor ac couples the MOUT output to the AIN pin.
Automatic Gain Control Register – AGCC
The AGCC register controls the overall function of the AGC circuit such as enable/disable, gain
control etc.
●● AGCC register
Bit
7
6
5
4
Label
RON AGCEN ADINS
—
R/W
R/W
R/W
R/W
R/W
3
2
1
0
—
RGS2 RGS1
RGS0
R/W
R/W
R/W
R/W
Bit 7
Bit 6
Bit 5
Bit 4-3
Bit 2-0
RON: AGC Charge Resistance control
0: off
1: on
AGCEN: AGC control
0: disable
1: enable
Note that if the AGC function is enabled, then pin PA0 will become an input pin and
will disable any interal pull high options automatically.The AGC function can be
disabled to reduce power consumption.
ADINS: ADC input control
0: NOT filtered via the SCF
1: filtered via the SCF
unimplemented, read as “0”.
RGS2~ RGS0: Amplifier Gain control
000: 1.16
001: 1.56
010: 2.22
011: 2.91
100: 5.09
101: 8.91
110: 13.82
111: 25.97
Rev. 1.00
137
April 01, 2011