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參數(shù)資料
| 型號： | AS2524 |
| 廠商： | ams |
| 文件頁數(shù)： | 3/20頁 |
| 文件大?。?/td> | 0K |
| 描述： | IC LINE INTERFACE/SPKRPH 28-SOIC |
| 標準包裝： | 27 |
| 系列： | * |
Data Sheet AS2523, AS2524, AS2524B
austriamicrosystems
Revision 1.13
Page 10 of 19
Programming Guidelines for the AS2523
The AS2523 is programmed by means of a serial 8-bit shift
register. MSB is clocked in first, LSB last.
The first four bits (7,6,5,4) are the addresses of the
registers, the last four bits (3,2,1,0) are the data bits.
Each register has a default setting (see data sheet), which
is set after power-up of the chip.
The internal registers are RAM-cells. When the AS2523
loses VDD (as in on-hook state) it also loses the register
contents.
It is therefore necessary to re-write the affected registers
after each hook event. The register contents cannot be
read, they can only be written.
Registers need to be re-written after each power-up and
after each hook event (handset / handsfree / on-hook).
It is recommended to always initialize the chip with a “reset
to defaults command” (Fx) first and then write the
appropriate registers that need to be changed from the
default setting.
Alternatively, all registers (4 to 16) may be re-written in a
bulk at each power-up and hook event (handset /
handsfree / on-hook).
This guarantees safe operation in case of unexpected loss
of power during normal operation. Re-writing all registers
also eases later software updates, as only register
contents need to be changed, but no additional command
lines need to be inserted.
Example of a typical power-up sequence
A typical power-up sequence will require the following
programming.
a) determine the cause of power-up (handset / handsfree
mode) and set register D accordingly.
Default = handset mode
b) Set the LI voltage to 3.5V or 4.5V (default = 4.5V) and
Line Loss Compensation (default = off) in register 4
c) Set the Confidence Tone level (e.g. the DTMF level
which is audible in the handset) and path in register 5
Default = off
d) Set the required Tx and Rx gains in Registers A and B
Default = 37dB Tx gain, 1dB Rx gain
Additional settings in Handsfree mode
Note: change the default settings only if necessary:
a) A click-free startup can be achieved by starting up in
handset mode (=default) and then switching to
handsfree, once the chip has stabilized.
b) Change the Tx comparator preamplifier gain in register 6
Default = 14dB
c) Change the Receive DC offset and Background noise
monitoring in Register 7
default = 0mV offset (higher val. puts more weight on Rx)
switching delay default = on
Background Noise Monitoring = on
d) Set the speaker amplifier volume in register 8
Default = 0B
e) Set the handsfree voice switching speed and
Background Noise monitoring offset in register 9:
default voice switching speed = 1ms/6dB (fastest)
default BGN monitoring offset = 240mV (determines the
Tx level required to switch from idle to Transmit)
Additional settings during Flash
During a Flash, the AS2523 should be powered down to
avoid discharge of VDD:
Set the MASK bit (bit3 in register D) to 1
After the line current is restored, the MASK bit must be
cleared again. Other settings do not need to be re-written,
as VDD has not discharged. As a safety margin however, it
is recommended to re-write all registers after a flash
Additional settings during line breaks
If a line-break-detection (brief interruption of the line while
in off-hook state) is implemented, the same rules apply as
for a Flash: set the MASK bit to 1 to avoid discharge of
VDD. It is recommended to re-write all registers after a
line-break, as a line break may take long enough to
discharge VDD, even when the MASK bit was set.
General Rules
The serial interface may be programmed at any time, it
does not affect the speech quality, e.g. if a register is
overwritten with the same value.
It is also possible to re-write all registers periodically. The
register is static, therefore it can be clocked at any speed
up to 5MHz.
However, electromagnetic pulses on the clock and data
lines may cause unwanted programming of the chip. It is
therefore recommended to keep these lines short, filter
them by a discrete lowpass filter and reduce the clock
speed accordingly.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AS25-24 | 制造商:ASTRODYNE 制造商全稱:Astrodyne Corporation 功能描述:25W Single Output Switching Power Supply |
| AS2524 T | 制造商:ams 功能描述:IC LINE INTERFACE/SPKRPH 28-SOIC |
| AS2524B | 制造商:AMSCO 制造商全稱:austriamicrosystems AG 功能描述:Telephone Line Interface and Speakerphone Circuit |
| AS2524BF | 制造商:AMSCO 制造商全稱:austriamicrosystems AG 功能描述:Telephone Line Interface and Speakerphone Circuit |
| AS2524BT | 制造商:AMSCO 制造商全稱:austriamicrosystems AG 功能描述:Telephone Line Interface and Speakerphone Circuit |
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