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參數資料
| 型號： | EVAL-AD7879-1EBZ |
| 廠商： | Analog Devices Inc |
| 文件頁數： | 25/41頁 |
| 文件大小： | 0K |
| 描述： | BOARD EVALUATION FOR AD7879-1 |
| 標準包裝： | 1 |
| 主要目的： | 接口，觸摸屏控制器 |
| 嵌入式： | 否 |
| 已用 IC / 零件： | AD7879-1 |
| 主要屬性： | 4 線電阻式觸控屏控制器，I²C 和 SPI 接口 |
| 次要屬性： | 圖形用戶界面，USB 接口 |
| 已供物品： | 板，線纜，CD，觸控屏 |
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AD7879/AD7889
Rev. C | Page 30 of 40
INTERRUPTS
The AD7879/AD7889 have a dual function interrupt output,
INT, as well as a pen-down interrupt, PENIRQ. The INT output
can be configured as a data available interrupt (DAV), as an
out-of-limit interrupt (INT), or as a GPIO interrupt.
DAV—Data Available Interrupt
The behavior of the interrupt output is controlled by Bit 13 in
Control Register 3. In default mode (Bit 13 = 0), INT operates
as a data available interrupt (DAV). When the AD7879/AD7889
finish a conversion or a conversion sequence, the interrupt is
asserted to let the host know that new ADC data is available in
the result registers.
While the ADC is idle or is converting, DAV is high. When the
ADC has finished converting and new data has been written to
the result registers, DAV goes low. Reading the result registers
resets DAV to a high condition. DAV is also reset if a new con-
version is started by the AD7879/AD7889 because the timer
expired. The host should read the result registers only when
DAV is low. To ensure correct operation of the DAV mode
when using the SPI interface, it is necessary to write 0x0000
to Register 0x81 after a set of register reads. This clears the
internal data read signal.
ADC
CONVERTING
SETUP
BY HOST
IDLE
NEW DATA
AVAILABLE
HOST READS
RESULTS
IDLE
tCONV
AD7879/
AD7889
STATUS
DAV
07667-
034
Figure 35. Operation of DAV Output
When the on-board timer is programmed to perform automatic
conversions, limited time is available to the host to read the
result registers before another sequence of conversions begins.
The DAV signal is reset high when the timer expires, and the
host should not access the result registers while DAV is high.
INT—Out-of-Limit Interrupt
The INT pin operates as an alarm or interrupt output when
Bit 13 in Control Register 3 (Address 0x03) is set to 1. The
output goes low if any one of the interrupt sources is asserted.
The results of high and low limit comparisons on the AUX,
VBAT, and TEMP channels are interrupt sources. An out-of-
limit comparison sets a status bit in the interrupt register. A
separate status bit for the high limit and the low limit on each
channel indicates which limit was exceeded. The interrupt
sources can be masked by setting the corresponding enable bit
in this register to 1. There is one enable bit per channel.
PENIRQ—Pen Interrupt
The pen interrupt request output (PENIRQ) goes low whenever
the screen is touched and the PENIRQ enable bit is set to 0
(Control Register 1, Bit 15). When PENIRQ enable is set to 1,
the pen interrupt request output is disabled.
The pen interrupt equivalent output circuitry is shown in
Figure 36. This digital logic output has an internal 50 k pull-
up resistor, so it does not need an external pull-up. The
PENIRQ output idles high, and the PENIRQ circuitry is always
enabled in master mode (ADC mode = 11), except during
conversions.
07667-
035
X+
TOUCH
SCREEN
Y+
50k
Y–
X–
PENIRQ
ENABLE
PENIRQ
VCC
Figure 36. PENIRQ Output Equivalent Circuit
When the screen is touched, PENIRQ goes low. This generates
an interrupt request to the host. When the screen touch ends,
PENIRQ immediately goes high if the ADC is idle. If the ADC
is converting, PENIRQ goes high when the ADC becomes idle.
The PENIRQ operation for these two conditions is shown in
07667-
036
SCREEN
PENIRQ
ADC
STATUS
TOUCHED
NOT
TOUCHED
NOT
TOUCHED
NOT
TOUCHED
NOT
TOUCHED
ADC IDLE
SCREEN
PENIRQ
ADC
STATUS
TOUCHED
ADC IDLE
ADC
CONVERTING
ADC IDLE
RELEASE NOT
DETECTED
PENIRQ
DETECTS
RELEASE
PENIRQ
DETECTS
RELEASE
PENIRQ
DETECTS
TOUCH
PENIRQ
DETECTS
TOUCH
Figure 37. PENIRQ Operation for ADC Idle and ADC Converting
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| EVAL-AD7879EBZ | 功能描述:BOARD EVALUATION FOR AD7879 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估演示板和套件 系列:- 標準包裝:1 系列:- 主要目的:電信，線路接口單元（LIU） 嵌入式:- 已用 IC / 零件:IDT82V2081 主要屬性:T1/J1/E1 LIU 次要屬性:- 已供物品:板，電源，線纜，CD 其它名稱:82EBV2081 |
| EVAL-AD7887CB | 制造商:Analog Devices 功能描述:EVAL BD FOR 2.7 V TO 5.25 V, MICROPWR, 2CH, 125 KSPS, 12-BIT - Bulk |
| EVAL-AD7887CB4 | 制造商:AD 制造商全稱:Analog Devices 功能描述:2.7 V to 5.25 V, Micropower, 2-Channel, 125 kSPS, 12-Bit ADC in 8-Lead MSOP |
| EVAL-AD7887CBZ | 功能描述:BOARD EVAL FOR AD7887 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - 模數轉換器 (ADC) 系列:* 產品培訓模塊:Obsolescence Mitigation Program 標準包裝:1 系列:- ADC 的數量:1 位數:12 采樣率（每秒）:94.4k 數據接口:USB 輸入范圍:±VREF/2 在以下條件下的電源（標準）:- 工作溫度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板，軟件 |
| EVAL-AD7888CB | 制造商:Analog Devices 功能描述:EVAL KIT FOR 2.7 V TO 5.25 V, MICROPWR, 8CH, 125 KSPS, 12-BI - Bulk |
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