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參數資料
| 型號： | HT82A821R_07 |
| 廠商： | Holtek Semiconductor Inc. |
| 英文描述： | USB Audio MCU |
| 中文描述： | USB音頻控制器 |
| 文件頁數： | 20/39頁 |
| 文件大小： | 275K |
| 代理商： | HT82A821R_07 |
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HT82A821R
Rev. 1.10
20
June 29, 2007
DAC_Limit_Land DAC_Limit_H are used to define the 16-bit DAC output limit. DAC_Limit_Land DAC_Limit_H are un-
signed value. If the 16-bit data from Host over the range defined by DAC_Limit_L and DAC_Limit_H, the output digital
code to DAC will be clamp.
DAC_Limit_L
DAC output limit low byte
DAC_Limit_H
DAC output limit high byte
Setting DAC output limit value example:
;-----------------------------------------------------------
; DAC Limit POR Value=8000H
; Set DAC Limit Value=FF00H
;-----------------------------------------------------------
clr
[02DH]
; Set DAC Limit low byte=00H
set
[02EH]
; Set DAC Limit high byte=FFH
;-----------------------------------------------------------
In order to prevent the pop noise of speaker output, power amplifier should be output at the value of VDD/2 (send
8000H to DAC) during the initial power on state. If software set high then clear the bit DAC_WR_TRIG (bit 3 of
DAC_WR register), the value on the DAC_Limit_L and DAC_Limit_H registers will write to DAC.
Bit No.
Label
R/W
Power-on
Functions
0~2, 4~7
R
0
Undefined bit, read as 0 .
3
DAC_WR_TRIG
R/W
0
DAC write trigger bit
DAC_WR (2FH) Register
Example to avoid popping noise:
System_Initial:
;-----------------------------------------------------------
; Avoid Pop Noise
;-----------------------------------------------------------
mov
a,WDTS
mov
FIFO_TEMP,a
;Save WDTS value
mov
a,01010000b
andm
a,WDTS
mov
a,01010000b
orm
a,WDTS
;Enter DAC Write Data mode, high nibble of WDTS=0101b
clr
[02DH]
;Set DAC data low byte=00H
mov
a,80H
mov
[02EH],a
;Set DAC data high byte=80H
nop
;Write 8000H to DAC
set
[02FH].3
nop
clr
[02FH].3
nop
;-----------------------------------------------------------
mov
a,FIFO_TEMP
;Restore WDTS value
mov
WDTS,a
;Quit DAC Write Data mode
;-----------------------------------------------------------
Note: At DAC write data mode (high nibble of WDTS register is 0101b), DAC_Limit_Land DAC_Limit_H registers will
be the 16-bit DAC input data register at falling edge of DAC_WR_TRIG. Otherwise, these two registers are
used to define the 16-bit DAC output limit.
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|---|---|
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相關代理商/技術參數 |
參數描述 |
|---|---|
| HT82A822R | 制造商:HOLTEK 制造商全稱:Holtek Semiconductor Inc 功能描述:USB Audio MCU |
| HT82A822R_07 | 制造商:HOLTEK 制造商全稱:Holtek Semiconductor Inc 功能描述:USB Audio MCU |
| HT82A824R | 制造商:HOLTEK 制造商全稱:Holtek Semiconductor Inc 功能描述:USB Audio MCU |
| HT82A832R | 制造商:HOLTEK 制造商全稱:Holtek Semiconductor Inc 功能描述:USB Audio MCU |
| HT82A832R_07 | 制造商:HOLTEK 制造商全稱:Holtek Semiconductor Inc 功能描述:USB Audio MCU |
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